I feel like i should add that there seems to be a large misconception of the word "tyrannical" when used to describe the government. It seems that most people assume this means a government wanting to commit genocide, class extermination, random killings, etc.... While the word does encompass those things, it's more focused on the abuse of power by instituting laws and regulations that limit our pursuit of happiness. The abuse of power that can infringe upon our inalienable rights as not only Americans but as humans.
A genocidal government is very worst case scenario. Maybe what's easier to imagine is a government hell bent on taking your freedom to gainful employment, freedom to be an entrepreneur, freedom to become what ever it is you want to become or your freedom to pursue what ever it is that makes you happy.
When these things happen.....
But when a long train of abuses and usurpations, pursuing invariably the same object evinces a design to reduce them under absolute despotism, it is their right, it is their duty, to throw off such government, and to provide new guards for their future security.