I contribute to some FOSS projects with hundreds of thousands of downloads and it's healthy from several points of view.
On the one hand, I made some great "online" friends and feel great as I write code that I know people will use and appreciate. On the other hand, I've learnt so much and I know that some of the skills I've acquired during these years will help me when I'm old enough to get a job and start "actually" working. I feel like I can also say Open Source will make the man I will be.
To me, it's amazing how I can sit back in my desk and shape projects being developed and used by people from all over the world. I rarely have time to think about the awesomeness in that, but when I do I always feel so fulfilled.