Another complicating factor was that, as far as the colonists were concerned, they wanted to be citizens of England and loyal servants of the Crown. However, the powers-that-were in England really saw them as nothing more than a useful resource. An those powers were concentrated in Parliament, which took control of the colonies.
The anger of the colonists rested on this: they were Crown colonies. It was right in their charters that they reported to the King. As was usual in English history, the weak wanted to ally with the strongest (George III) in order to bypass the intermediate powers (Parliament). However, George was quite a waste of human flesh and had more or less been completely dominated by his advisors - mostly influential nobles. The result was that a trend of Parliament taking monarchial privelege continued and they began tossing off edicts to the colonies.
Well, that did not go over well, because the colonial legislatures were legally about equal with Parliament. They probably would have been willing to go along, except that said edicts were rather bloody-minded, insulting, and poor policy, aimed at sacrificing the livelihoods of colonists in favor of England. This, of course, was the common and completely backward economic thought of the day. Hence trade was to be controlled, colonists subject to strict English rule*, and dissent tolerated very little. Worse yet, the King then handwaved their complaints and treated them as subjects - and that’s when discontent turned to white-hot rage. The King had, in essence, declared that they were not citizens, but subjects without rights to be respected.
Trade was certainly an issue: many of the msot successful Americans involved themselves in American trade with other nations’ colonies. It was, in fact, almost necessary for the colonies to function. Meanwhile, the Crown kept the colonies from building their own industry and manufactures, to keep the colonies from competing with English and Scots merchants. This was another huge sore point.
Now, it may be fairly said that Britain defended the colonies. However, the colonists need never have been involved in the French and Indian war if not for Britain. France had no beef with the, and in fact would prove to be the best ally of the early Republic.
In short, the young America was trying very hard, and wanted very much, to become as great a land as England. They saw themselves as British, and rebelling against an arrogant and dismissive central power is very English. Many fo the founders had been personally insulted by the powers of England - but they did not rebel because of the insults, but because the insults were such a basic part of the attitude of that very British establishment.
*OK, a few Scots, too, but this was still a time when England very much dominated Britain. It was mostly Englishmen making the decisions, not colonists. Now and then the governers appointed were colonists though. Ben Franklin’s son was serving as Royal Governer of New Jersey at the time of Revolution, to which post he was appointed in order to shut up his dad. (Didn’t work, but it created a crushing family feud that completely broke the Franklin family.)