"We don't quit! We dont quit!"

When does a person not quit his job, even with less/no payment, no organised agendas, and sometimes crappy sucking up work/no legible work?

When he is passionate about what he might achieve later?
When he strived months becoming years to get to that place?
When he has patience to go through with it?
When he consoles himself that everywhere its happening to everybody, hence doesnt matter?
When he thinks holding on to it is like a string to a promised future and leaving it might be letting go of it completely?
When he becomes too comfortable with it and is scared to come out of it?

I dont know which of this I am.