The Boston Massacre and the Intolerable Acts were two of the main events (of many things that built up) that led the colonists to declare independence.
Other things that the colonists were unhappy about were the Townshend Acts, the Olive Branch Petition, the Tea Act, the Sugar Act, the Writs of Assistance, the Stamp Act, etc.
Colonists were angry about taxes and felt like foreigners, Trading policies
There were several determining factors,
One was taxation without representation, colonies were upset by England taxing them for supplies needed in their colonies. The king would make life there almost impossibly hard for colonist. There were several other conflicts such as the fact that they had no freedom of religion, they were forced to have the religion that the king George had. Eventually the colonists became weary of this and decided freedom was there only choice, this is when the document called "common sense" was published allowing, which spoke of independence from the king.
Explanation: