The American colonists began 1763 totally loyal to the British crown and very, very grateful for the king’s support during the French and Indian war. Because of British military might, the colonists were poised to move into the Ohio River Valley and their greatest rival in North American was no longer a threat.
However, things began to change when Parliament passed a law preventing colonists from crossing the Appalachian Mountains. The sense of betrayal was instantaneous and permeated all levels of colonial society. If the king was willing to restrict their movement into an area they had fought and bled for, what else would he be willing to do?
Soon, there would be additional taxes as well. Betrayal was soon back in the colonial mindset, this time in the form of taxation without representation. Up to this point they had always been consulted before tax rates changed, but now it seemed they were too insignificant to warrant even a letter about the upcoming changes in imperial policy. This had a large effect on the colonial psyche and soon it had manifested itself into full-blown civil disobedience.
By the time of the Boston Massacre, it was too late for cooler heads to prevail. Colonists from all walks of life were convinced that the British were evil and that they were the enemy.