I find that my personal projects are the ones that get the most visiblity and recognition. If I were to think of purely in terms of am I getting cash for this time - then I would probably never spend time on any project or startup where there was no money in it for me right away.

Think about all those open source projects on GitHub - if nobody ever worked "for free", you would get such great wonderful projects like some amazing jquery pluggins and what not.

I think when people think in a small short term view like this, they severely limit themselves.