Well, it most certainly didn't happen right away. It took several tough times to push people to want them to fight for their rights. In 1764 the British Government enforced taxes on items. There were also many unfair laws. Colonists began protesting in Boston in 1765. This was the Boston Tea Party.
Colonists through tea into the water because they were putting taxes on the tea. Eventually events became so bad a war was started. The two battles were Lexington and Concord.
The American Revolution lasted from 1765 to 1783. This eventually led to the war of 1812. This war was between the United Kingdom and the United States. It ended in 1815.