What are some shared factors in the revolutionary movement?

Revolutions happen a simple reason, they happen out of a populist (not popular) desire for any or all of the following: freedom (from slavery, from want, want oppression, etc), liberty (the right to free movement and free thought), equality (for gender, sexual orientation, religion, etc), self-determination and democracy.
Revolutions don't have to be bloody (French, American) they can be very quiet (Industrial) and even, on occasion, go unnoticed (technological).
There is no simple list of factors as each revolution has distinct stages and aspects peculiar to their themselves but to root reasons for their beginnings can be based in some form of the above list.