It's true at first when you work on your own stuff you have this great level of enthusiasm, but eventually like any other kind of work it becomes a grind. It is my personal opinion that people who are not passionate enough to get started at night when working a 9-5 job, are probably not passionate enough to be self starters completely on their own. But again it's just MY opinion and obviously I would need to know OP personally to make more than a grand generalization.