You should try to do whatever makes you happy. If it makes you happy to give your labor away for free to some large profitable company, then by all means do so. I would personally try to use my time for myself (either to make more money or to do things I enjoy), but it's a personal choice after all. Only you can make that choice.
That said, having balance is usually a good idea. If you have interests indepedent of your work, you will be able to lean on those interests when work isn't going well. This may not seem important now, but some day you may find yourself tired and lonely working late at night without seeing the fruits of those labors and suddenly your stuck with nothing else going on in your life.
I know that (I learned it at 25 though) but I don't regret being 19 and unbalanced. I had fun in the end. Suffering is a universal human experience and not something to be avoided at all costs or anything.
I mean, sometimes we give young people advice and they are super eager to do everything right and use all the lessons the older people learned. I figure, there may be value in learning that particular lesson on one's own and on one's own time.
The recent Tesla news are a good warning bell against never learning it, though. As was in a different way the recession.
> I figure, there may be value in learning that particular lesson on one's own and on one's own time.
I smart man learns from his mistakes. A wise man learns from the mistakes of others. I mean sure I also went through similar unbalanced years as you and I learned from them, but if I could go back and change something I would instill some more wisdom in myself earlier. I don't live regretting that time of my life, but if I had the chance I'd certainly do it differently.
That said, having balance is usually a good idea. If you have interests indepedent of your work, you will be able to lean on those interests when work isn't going well. This may not seem important now, but some day you may find yourself tired and lonely working late at night without seeing the fruits of those labors and suddenly your stuck with nothing else going on in your life.