@jennythelib - I never thought of it that way! But even though the colonists wound up turning on monarchy in general, it's important to remember that the British had long thought of themselves as a "free people." The UK is, and has been since I guess 1215, a constitutional monarchy, rather than an absolute one like the French monarchy.
Tyranny is in the eye of the beholder, I guess! George III was interfering with the colonists' daily lives, therefore they perceived him as a tyrant. Some historians think that the American Revolution owes its inspiration to the Glorious Revolution of 1683, in which James II was basically fired as king and a new king was interviewed and hired in his place (William, whose claim to the throne was through his wife, Mary, James's daughter; they ruled together). The idea was that the idea that people have a say in how they are governed was not new-born in America, but actually had a long history in England.