The rebel spirit has come to be universally associated with the United States of America. It's little wonder—our nation was founded in direct defiance of British rule and authority. A dedication to individualism consequently became a mark of Americans, and it has affected our religion, politics, primary and secondary education, scholarship, athletics, entertainment, etc.
This ideology wasn't born in a vacuum. The founders of the U.S.A. were all children of the Enlightenment: some of them consciously and eagerly so, others simply because they lived within its milieu. Enlightenment philosophy was built on the idea that Man is constantly evolving and progressing toward a state of perfection in which there will be no war, injustice, or possibly even death.
Basically, it's the secularized version of the Christian hope in the Kingdom of Heaven. The major difference is that it leaves out God, and while some attempted to reconcile their Enlightenment ideals with the Christian faith, many simply abandoned their faith or bent it out of all recognizable shape (deism was popular, and there were even a few atheists).
As part of this inevitable progress, the founding of a new government and constitutional body was seen as an unmistakable step forward. Of course, more than just altruistic principles were at work. The colonists felt that British impositions on their commerce in the form of taxes was best thrown off for the good of the burgeoning economy. Most famously, this resistance to taxation led to an act of extreme vandalism on December 16, 1773.