Everyone on this Earth, whether they realize it or not, has something worth fighting for.  Something that makes the deepest darkness fathomable and the deepest pains tolerable. Perhaps it's love that drives you, or perhaps it's the desire for knowledge, or even just a stubborn determination to persist, or a fear of what would happen if you do not.  But if there is anything my teaching and experience in psychology is that no one who wishes to fix themselves is beyond redemption.

Sometimes, I think that I fight and persist because I do not know how to do otherwise.

Others, I merely see the smile in @katiekat's words, and I know why I do.