Being a self-starter is the same as being the last to quit, give up, give in, and sign off. Nothing ever happens unless one initiates and keeps trying what was started—with creativity that comes from continuous learning to give you new ideas and approaches.
There will always be endless reasons to cave in "this one time" because you are tired, sick, mad, put down, challenged, threatened, beaten, or bullied—or whatever other reason you give yourself. Stick to it. Don't give up, walk away, or abdicate your promise to yourself.
Debra Benton has a new book from McGraw-Hill (June, 2017) titled, The Leadership Mind Switch: Rethinking How We Lead in the New World of Work.