in order to fund the war; the Sugar Act of 1764 and the Stamp Act of 1765 are just some of the laws that were created and passed with the purpose of getting more money from the American colonists. Naturally, many of the colonists did not appreciate the new laws and tried to appeal to the British government. However, the British leaders believed that it was right to tax the American colonists, because, according to them, the British army fought hard to protect the Americans during the war, and one way the American colonists could express their gratitude is to pay taxes, so that the debt can be repaid sooner.

Many of the colonists disagreed with these claims, as they believed that the main reason why the British Empire funded the war was to expand both its territory and influence, and not to protect or appease the colonists. Furthermore, the American colonists were largely underrepresented in the British legislative body and the British government in general; thus, they remained powerless when it came to the decisions made about their socioeconomic status, as the British parliament consisted mainly of British individuals who were chosen by the English population in Great Britain.

Even though some colonists did not want to meddle in politics, a big number of them also began to think about independence and decided to try to get as many people as they could to resist and ultimately put a stop to the British rule over the colonies. Soon, the growing displeasure with the British Empire's governance grew into a war of independence and marked the start of the American Revolution.

Americans considered themselves to be British citizens, but the Americans in the colonies were not treated the same as citizens living in England. As war with England became imminent, the colonies first made their complaints known to King George in the Olive Branch Petition. In this petition, the leaders of the First Continental Congress expressed issues the colonists felt were oppressive. One key complaint in the petition, and which would be a reason for war, was taxation without representation. The British government taxed the American colonists, but the colonists had no representation in Parliament. Without representation in Parliament, the American colonists had no outlet in matters of government yet still had to pay taxes.

In addition, the taxes against the colonists were the British response to paying for a war of their own.  The British had just won the French and Indian War in 1763. The colonists and Great Britain disagreed over who was responsible for the war debt. Colonists saw this war as Britain’s way of strengthening their empire. England saw this war as an aid to American colonists, and American colonists should pay the war debt. England began taxing the colonists in a variety of different taxes such as the Stamp Act.

By the time the Second Continental Congress met, the Declaration of Independence had been drafted, and this document outlined a total of 28 grievances the American colonists had with the British government.  

The American colonists fought the British for one main reason.  They fought because they wanted to be independent.  Since you ask for two reasons, I assume that you need two reasons why they wanted to be independent.

One reason the American colonists wanted to be independent was British taxation.  Many Americans did not think that the British government had the right to tax them.  They felt that taxes on things like exports were okay, but taxes on things that they bought and sold within their own borders were not.  This is why they were so strongly opposed to the Stamp Tax.  They also did not like the idea of being taxed by a legislature in which they were not represented.  Opposition to British taxation, then, was one reason why the Americans wanted to be independent.

A second reason the colonists wanted to be independent was manufacturing and trade.  The American colonists wanted to be able to make whatever goods they liked.  The British did not allow this because they did not want the colonists to compete with British producers of a variety of goods.  The Americans also wanted to be able to trade with people from any country they liked.  The British did not want this because they wanted all colonial trade to go through Britain and thereby make Britain richer.  The colonists did not like having their commerce restricted in order to help the British.

So, we can say that taxation and restrictions on manufacturing and trade were two reasons why the American colonists wanted independence badly enough to fight for it. 

We can generally say that there were four main causes of the American Revolution.  These causes mostly came into being after the French and Indian War.  It was only after this war that relations between England and the colonies really deteriorated.

The first cause was more of a condition that allowed the revolution to happen.  This was the fact that the British drove France out of North America in the French and Indian War.  This meant that the Americans no longer had to fear being conquered by the French if they became independent.

The second and third causes were tied directly to the actions of the British government.  Both of these came about because the government needed money to defray the costs of the French and Indian War.  First, the British increased their regulation of the American colonies.  They wanted to make sure that the colonists were obeying laws that were meant to help British finances.  This led the British to crack down on the colonists, angering the colonists who had been used to having more freedom.  Second, the British started to tax the colonists more.  The British did this to get money, but they did so without consulting the colonists.  The colonists felt that both of these British actions were infringements on their liberties.

Finally, the revolution came about simply because the colonies had outgrown colonial rule.  Colonial rule becomes harder and harder to impose as the colony becomes bigger and more prosperous.  By 1776, the American colonies had become larger and wealthier and no longer felt the need or the inclination to accept British rule.

All of these factors combined to bring about the revolution.

To answer this question, it is necessary to look at a number of issues. Let us look at a few.

First, one must consider the justice of the claim most often associated with the revolutionaries, which was that Parliament had no authority to enact taxes on the colonies because the colonists were not represented in that body. This is a debatable claim, especially since almost no British people could vote for Parliament and were therefore not represented either. So the claim that a fundamental right was being violated has to consider this reality.

Another issue that might be considered is the effects of British policy. For example, many colonists had hoped to settle west of the Appalachian Mountains following the French and Indian War. But their aspirations were crushed by the Proclamation of 1763, which banned colonial settlement west of the Appalachians.

On the other hand, the British undertook this measure in an effort to avoid endemic conflict with Native peoples, who would surely resist expansion. Also, the people most affected by this were large land speculators, not ordinary colonists. Still, this could be seen as a clumsy policy at best, one that did not acknowledge realities in the colonies.

If permissible, it might make sense to narrow the question down or to look at a British action that did, in fact, warrant armed resistance. Some might argue that the so-called "Intolerable Acts" passed after the Boston Tea Party were the point at which the colonists were justified in launching a revolution.

An excellent source for this activity would be the Declaration of Independence itself. The first, well-known part of the Declaration attempts to argue that the colonies are justified due to British violations of natural la and the social contract that binds people to government. But the most important part of the document in its own time was perhaps the list of grievances, each of which attempted to justify rebellion and independence.

The American colonists had many grievances against the British government, but the straw that broke the camel's back fact that they were having laws made about their own lives without any representation in the British Parliament. The British government was passing laws and, in particular, levying heavy taxes against the colonists to fund their other efforts. Because of this, American colonists were paying exorbitant rates on imports like sugar, tea, paper products, and much more that would have been significantly cheaper in Britain. All the while, they had no voting power and no representation in Parliament and were essentially not true British citizens.

Because they were unable to elect anyone to Parliament, the colonists had absolutely no power to put anyone in place to change these laws. (Even if they did, the only people who were allowed to be elected were those that lived in Britain.) Therefore, they came up with the famous cry "No taxation without representation," essentially encapsulating the idea that they had no voice in the government and were being taxed without their consent. Because of this, they rebelled and began the Revolutionary War.

The founders of the United States of America justified declaring independence from Great Britain in the Declaration of Independence. The Declaration states that the people of the Thirteen Colonies had suffered a "long train of abuses and usurpations" at the hands of the British government. They say that they repeatedly petitioned the Crown and the people of Great Britain to address these complaints but were denied each time. Since, according to the Declaration of Independence and notions of Enlightenment philosophy, a government's responsibility is to protect the rights of its citizens, and the British government has failed to do so, the people are justified in their rebellion.

The abuses that the founders cite range widely. They include the institution of taxes without the consent of the people and the lack of due trial. They also include more dire accusations such as sending mercenary armies to destroy their homes and murder them. All these things and more make the rebellion justifiable.

Of course, many people in the colonies felt that rebellion against the Crown was an immoral and treasonous act. However, the desire and motivations for independence and self-rule were strong enough to fuel a successful rebellion.

The American colonists were justified in rebelling against Great Britain and then declaring their independence. The colonists felt the British were treating them poorly and violating their rights.

After the French and Indian War ended, the British got control of most of the land France controlled east of the Mississippi River. The colonists wanted to move to these areas so they could own land. However, the Proclamation of 1763 prevented this from occurring. The colonists also weren’t happy they had to provide housing for the British troops that were enforcing this unpopular law.

The colonists felt the British were violating their rights. When the Stamp Act and the Townshend Acts were passed, this was done without the colonists having representatives in Parliament that could speak about and vote on these laws. The colonists insisted that all British citizens have the right to be represented in Parliament and have their representatives vote on proposed laws. The British insisted they had the right to pass these laws, and the taxes went into effect.

The colonists were upset with other British actions. When five colonists were killed in the Boston Massacre, many colonists were concerned. The colonists objected to the Tea Act because it gave a monopoly on the tea trade to the British East India Company. It also continued the tax on tea. When the colonists responded with the Boston Tea Party, the British responded with the Intolerable Acts. These laws were designed to punish the colonists, especially those in Massachusetts, for the Boston Tea Party. The colonists refused to obey these laws, and they formed their own militias. When fighting broke out at Lexington and at Concord, many people knew it was only a matter of time before we would declare our independence.

When the Declaration of Independence was written, it stated that if the government doesn’t protect the rights of the people, then the people must replace the government. The colonists believed the British government wasn’t protecting their rights. Thus, the colonists had no choice but to replace the government by declaring independence from Great Britain.

Regarding a question such as this, it is worth noting that there were divisions among the colonists themselves (and a significant loyalist contingent wished to remain with Britain). Regardless, the American Revolution had its foundations in the long established traditions of colonial autonomy and self-governance, which dates back to the early history of American colonization.

With the end of the French and Indian War, however, Britain embarked on a policy change regarding the colonies—to bring them more closely in line with British economic interests. Thus, the British government began to impose acts of colonial taxation and to actively enforce British mercantile laws. The result was to inspire a backlash against these policies within the Colonies themselves (a backlash that would gradually intensify across the course of time).

Meanwhile, when reading the Declaration of Independence, you might well notice the influence of Enlightenment philosophy, particularly the work of John Locke and its concerns with tyrannical governance. There is a sense, in this document, that British policy in the pre-Revolutionary period was understood in terms of an abuse of power and an infringement upon colonial rights. Thus, the Revolutionaries argued that Britain had actively betrayed its own responsibilities where the colonies were concerned. Rather than being a legitimate government, the Revolutionaries perceived Britain as a hostile, tyrannical foe.

The colonists wanted to break away from Britain for many reasons.  They had enjoyed a great deal of autonomy before the French and Indian War due to the British policy of salutary neglect.  After the war, Parliament became more strict in demanding money.  The colonists wanted to keep the money and not give it to Parliament, in which they were not represented.  Parliament responded that members do not necessarily represent their district; rather, one member can speak for the good of the entire realm.  

The colonists also protested the Proclamation Line of 1763, which gave Native Americans land west of the Appalachians.  A considerable part of the colonial economy was made up of land speculation—the colonists needed this new land and resented being told that they could not have it.  Also, many colonists started to question whether this move was actually for their safety. Some suspected that it was designed in order to make them easier to tax on the coast.  

Finally, the colonists felt as though their rights had been abridged.  Colonial tax dodgers could be taken to Britain and placed in front of a panel of judges rather than being judged by a trial of their peers back in the colonies.  The Boston Massacre occurred when British soldiers fired upon a mob near a customs house.  The Tea Act made the colonists pay a tax on tea whether they actually used it or not.  As a result, some colonists dressed up as Indians and threw the tea into Boston Harbor.  Parliament then levied the Intolerable Acts. This led to the city of Boston being occupied as it would be if it was conquered enemy territory.  The colonists felt oppressed and felt as though Britain was not treating them as British citizens.  This is why they decided to obtain independence.  

Reasons as to why the colonists decided to break away from Britain can be found in the Declaration of Independence.

Deteriorating relations between the colonists and Britain was occasioned by Britain’s insistence on increasing taxes on its colonies, which also maintained their status within the empire.

The issue about taxes, among other laws, was compounded by the fact that the colonies were not represented in the British Parliament. The colonists argued that the British Parliament’s capacity should be restricted to serving Britain only and allow them to focus on their own legislatures.

The colonists sought intervention from the king on laws that were determined to be contrary to the constitution. However, the king sided with the British Parliament and issued a Proclamation of Rebellion, adding to the tension and resentment on the side of the colonists.

The king failed to give dialogue a chance and instead prepared to use violence in order to crush the mounting rebellion.

There were several reasons why the colonists wanted to break away from Great Britain. One reason is that the colonists believed that the British were violating their rights by requiring the colonists to pay the taxes created by the Stamp Act and the Townshend Acts. The colonists believed that they should have had representatives in Parliament that could speak about and vote on the proposed taxes. Since they didn’t have representatives in Parliament, they felt their rights were being violated.

Another cause is that the colonists believed that the British were trying to control them. When the British passed the Proclamation of 1763, the colonists believed the British were trying to prevent them from getting the land that the British had received from France as a result of the French and Indian War. When the British passed the Quartering Act, which required the colonists to provide housing for the troops enforcing this unpopular law, they were even more upset. The colonists were also unhappy with the Tea Act. This law gave the British East India Company a monopoly on the trade of tea.

When events turned violent in the 1770s, more colonists began to think they needed to be free from British rule. In the Boston Massacre, five colonists were killed when British soldiers fired into a crowd of protesters. After the Boston Tea Party, the British passed the Intolerable Acts. These laws punished the colonists, especially those in Massachusetts, for the Boston Tea Party. After fighting occurred at Lexington and at Concord in April 1775, it appeared only a matter of time before the colonists would declare their independence from Great Britain.

The primary reason the colonists revolted was that they believed--correctly--that they had been denied their rights as Englishmen. There is some argument that after the French and Indian War, Americans developed a feeling of "separateness" from the Empire, that is that they were more American and less English. This feeling of separateness accelerated AFTER fighting broke out; however it was not the reason Americans rebelled in the first place.

After the French and Indian War, Britain took the unusual step of taxing the colonists for the cost of the war. Colonists had been taxed before, but those taxes had been levied by Colonial legislatures. They also had been taxed by Britain, but these taxes had been for purposes of regulation, rather than revenue. Most of the latter were simply evaded or ignored by the colonists as they smuggled goods to and from nations other than Great Britain. However, the attempt to tax the colonies (originally by the Stamp Act) violated one of the most sacred principles of the rights of Englishmen--the right to only be taxed by their duly elected representatives. Several English diplomats attempted to explain this away by arguing such things as "virtual representation," (Parliament represented the entire Empire) but this argument gained no ground. "Taxation without representation" soon became fighting words. Tensions soon ran high. James Dickinson expressed the feeling of the colonists eloquently:

Here then, my dear country men ROUSE yourselves, and behold the ruin hanging over your heads. If you ONCE admit, that Great-Britain may lay duties upon her exportations to us, for the purpose of levying money on us only, she then will have nothing to do, but to lay those duties on the articles which she prohibits us to manufacture- and the tragedy of American liberty is finished. . . . If Great-Britain can order us to come to her for necessaries we want, and can order us to pay what taxes she pleases before we take them away, or when we land them here, we are  as abject slaves as France and Poland can shew in wooden shoes, and with uncombed hair. 

 Dickinson may have overstated the cause; in fact even after fighting broke out, the colonists offered to return to the British fold provided they were guaranteed their rights as Englishmen.  They did this by means of the Olive Branch Petition:

The apprehension of being degraded into a state of servitude from the preeminent rank of English freemen, while our minds retain the strongest love of liberty, and clearly foresee the miseries preparing for us and our posterity, excites emotions in our breasts which, though we can not describe, we should not wish to conceal. Feeling as men, and thinking as subjects, in the manner we do, silence would be disloyalty. By giving this faithful information, we do all in our power to promote the great objects of your royal cares, the tranquility of your government and the welfare of your people.

 We ask but for peace, liberty, and safety. We wish not a diminution of the prerogative, nor do we solicit the grant of any newright in our favor. Your royal authority over us, and our connection with Great Britain, we shall always carefully and zealously endeavor to support and maintain.

By the time the Petition was sent to George III, feelings on both sides of the Atlantic had reached a fever pitch; at that point, there was no reasoning to be had, and the matter could only be settled with armed conflict. 

The American colonists rebelled because they felt that they were not being treated fairly by the English government.  As the colonies grew bigger and more prosperous, they came to feel that they should have more of the rights granted to people in England.  Most importantly, they felt that they should be free from taxation unless they were also represented in the legislature that voted for the tax.  

The colonists had been content to be colonies when British rule was "light" and when the colonies were small.  But as the colonies grew, and as the government in England became more controlling after the French and Indian War, the colonists started to rebel.

Perhaps the best place to look for the answer to this question is the Declaration of Independence. It provides an explicit justification for breaking away from Great Britain (which, by the way, even many revolutionaries had been uncertain about beforehand.) 

The Declaration says that:

...all men are created equal; that they are endowed by their Creator with certain unalienable rights; that among these are life, liberty, and the pursuit of happiness; that, to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed; that whenever any form of government becomes destructive of these ends, it is the right of the people to alter or to abolish it, and to institute new government, laying its foundation on such principles, and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness.

What this means, basically, is that all men are born with certain rights, and that the purpose of government is to protect those rights. The only legitimate government is one that preserves the rights of the people, and that is founded by their consent. If a government fails to protect the rights of the people, or are actually destructive of them, then the people have the right to replace it with another. 

The American revolutionaries argued that they had been the victims of a "long train of abuses" that gave them the right to break away from British rule. These included taxing the colonists without their consent, closing their ports, dissolving colonial assemblies and refusing to approve their laws, placing troops among them, and, in their words, encouraging "merciless Indian savages" to make war upon them. To the colonists, these offenses more than justified breaking away from Great Britain. They also thought, correctly, that declaring independence would open the door to loans from European nations necessary to fight the war, and to an alliance with France. But the moral and political justifications for independence are found in the document they used to explain their cause to the world.

In terms of the Revolutionary War, the ultimate expression of colonial rebellion, there were several reasons why it was waged.

Great Britain had defended the American colonies during the French and Indian War, and it wanted to be repaid for that defense because it effectively doubled the national debt for Britain. Moreover, the colonies had become very adept at smuggling, and so taxes and tariffs that should have gone to Britain went unpaid. Many in the American colonies wanted the freedom to transact business domestically and internationally without the burden of taxes and tariffs.

Many Americans not only wanted unrestrained trade with countries that were enemies of Great Britain but they also resented having to both help foot the bills for Britain's many wars with other nations. The quartering of British troops in American homes was also highly unpopular, as was forced military service on behalf of the crown.

The American colonies were not represented in Parliament. This angered many in the colonies who felt that they should have a voice in policy-making since many were paying increasingly onerous taxes, such as those levied by the Stamp and Townshend Acts. Interference in local legislatures in the colonies was also resented.

The colonists had numerous complaints about the governance they were subjected to. The colonists wanted to expand their territories past the Appalachian Mountains, which they were restricted from doing by the English government. The English had good reason to prevent this expansion, as there were contested claims of ownership over that land, and expanding into it raised the real possibility of war with France. The colonists eventually did start to claim land west of the Appalachian Mountains, which was one of the precipitating events of the French and Indian War. This war ended up being expensive for England, and new taxes were levied on colonial imports as a way to recoup some of the money spent during the war.

These new taxes were opposed by colonists because they raised the price of goods that were used relatively frequently. The colonists also complained because of the monopoly of the East India Company with regard to the trade in some goods, which had forced colonists to sell or buy goods at prices that they believed were unfair. There were also complaints from some colonists about being forced to house troops at their own expense (which was the impetus for the 3rd Amendment).

Ultimately though, not all colonists wanted to rebel. Approximately 20% of the colonists were Loyalists, while the majority of the colonists remained neutral. The population of patriots was likely between 25% and 30%, but they obtained significant help from France, which allowed them to succeed.

The colonists rebelled against England for several reasons. The colonists were upset with the tax laws that were passed. The colonists believed they should have a say about any tax law that would affect them. This is a basic right English citizens have. However, the colonists had no representatives in Parliament who could speak about or vote on proposed taxes. Thus, they resented taxes that came with the Stamp Act or Townshend Acts.

The colonists also believed the British were restricting their freedom. When the Proclamation of 1763 was passed, the colonists were not allowed to move west of the Appalachian Mountains. The colonists wanted to move to this area where they would be able to get land. Land ownership was very important to the colonists. Thus, they opposed this law. They also opposed the Quartering Act that required them to provide places for soldiers, who were enforcing this law, to live.

The colonists were concerned about the violence that occurred with the Boston Massacre and the harsh response by the British to the Boston Tea Party. When fighting occurred at Lexington and Concord in April 1775, many colonists felt going to war was the only option to resolve the differences that existed between the colonists and the British.

The American colonies revolted over what they perceived to be a lack of disrespect for their rights as British subjects. Britain practiced salutary neglect towards the colonies for years, thus granting them a bit of self-rule unofficially, as the colonists often found ways around following the British navigation acts and British taxation laws. After the French and Indian War, Britain sought to tighten its controls on the American colonies in order to strengthen the treasury. The colonists revolted as they stated that they were not represented in Parliament. Parliament countered that they were not a representative body and that they had a rightful duty to tax British subjects wherever they lived.

The American colonies also revolted against British punishments. After the French and Indian War, violators of the Navigation Acts could now be tried in front of Admiralty courts. This meant the lack of a jury trial. Britain also closed down the port of Boston and stationed troops there with the Quartering Act in retaliation for the Boston Tea Party. By the time of the Revolution, the colonists viewed Britain less as a benevolent mother country and more as a controlling government that did not have their best interests at heart.

There were several reasons why the colonists revolted against Great Britain. The three most important factors were taxes, control, and bloodshed.

Taxes
The British Parliament passed two tax laws that upset the colonists. Both the Stamp Act and the Townshend Acts violated the rights of the colonists, in their opinion. They believed that they needed to have representatives in Parliament who could speak about and vote on proposed tax laws. The colonists didn’t have representatives in Parliament. As a result, the colonists believed their rights were being violated.

Control
When Parliament passed the Proclamation of 1763, the colonists weren’t allowed to go to the lands that Great Britain gained from France in the French and Indian War. The colonists weren’t happy about this. To make matters worse, the colonists had to provide housing and supplies for the British soldiers that were enforcing this unpopular law.

Bloodshed
At the Boston Massacre, five colonists were killed. For some people, this was an important turning point in the relationship with Great Britain. After the Boston Tea Party, the British passed the Intolerable Acts, which the colonists refused to obey. When the British moved their troops to Lexington and Concord in April 1775, soldiers on both sides were killed. For many people, it was only a matter of time before the colonists would declare their independence from Great Britain. With the publication of Common Sense, a pamphlet written by Thomas Paine explaining why the colonists should declare their independence from Great Britain, more people were convinced that independence was justified.

There were many reasons why the colonists rebelled against Great Britain.

The American Revolution (1775–1783) resulted from numerous events and grievances that had steadily exacerbated relations between America and Britain. These events occurred between 1763 and 1776, and war ensued.

By the mid-18th century, the colonists and Britain had different social beliefs and economic interests. Mercantilism and the Navigation Acts were supposed to regulate trade between the two to Britain's advantage, but the colonists enjoyed a great deal of autonomy and the relationship was relatively harmonious.

In 1763, the French were defeated, and England became the hegemon of North America. This changed the relationship for the worse. The colonists knew they no longer needed English protection from the French. At the same time, England began to tax the colonists and enforce trade regulations more strictly. The Stamp Act of 1765 was the first major dispute. The Townshend Acts (1767) followed.

Colonists thought these measures—and the taxes they were designed to collect—were unfair. They claimed that they were not represented in Parliament, so it was taxation without representation. There were violent incidents, like the Boston Massacre (1770) and the burning of the Gaspee (1772).

A full-scale battle occurred at Lexington and Concord in 1775, and the revolution began. But many colonists were still reluctant to break from England; these people were known as Loyalists.

In 1776, two events caused an irreparable break. First, Thomas Paine wrote Common Sense—a convincing argument for independence. Then the Declaration of Independence made it official: the United States was proclaimed an independent nation.