there were .any reasons as to why, here are 3...
1. The distance between Great Britain and the US was far too great and this would lead to long waiting periods when the colonies needed to make laws.
2. when a country is separated from the rest of the world, it's inevitable that they begin to govern themselves.
3. Commerce, Paine says that commerce can be better conducted with the rest of Europe, but they can only do that if they become independent.