There were several reasons why the British got into a conflict with the 13 colonies. One reason was political. The British believed that since these were their colonies, they could do whatever they wanted with them. The British believed the colonists should not be telling them how to run the colonies. The purpose of having colonies was for Great Britain to benefit. Almost all decisions reflected this key idea. The colonists didn’t agree with that philosophy.
A second reason was economic. As the cost of running the colonies increased, the British believed the colonists should pay for some of these costs. The British believed the colonists were benefiting from being British colonies and, therefore, should share in some of the costs of running the colonies. Thus, the British passed tax laws that colonists opposed.
A third reason for the conflict was based on what rights the colonists had. The colonists believed they had the same rights as people living in Great Britain had. One of those rights was to have representatives vote on proposed taxes. The colonists had no representatives in Parliament that could speak about and vote on the tax laws that impacted the colonists. The colonists felt their rights were being violated. When the British refused to make changes, the colonists became more active in their protests. This escalated the issues between Britain and their colonies. Ultimately, blood was shed and war was declared after the colonists declared their independence from Great Britain.