I am ambivalent about this. A friend of mine was found dead in his house last year, a week or three after he died. Many of his closest friends had moved away to other continents; others were trying to respect his desire for privacy by not dropping in unannounced. He had his problems, but he was very well loved. But it wasn't enough.

I agree with you that it's important that we live our lives in such a way as to create happiness; I think it's okay whether the happiness is for ourselves or for others.

But I think that the most effective way to do that is to carry forward the advancement of human knowledge, because ignorance is the source of unhappiness. It's worth depriving oneself of a bit of day-to-day pleasure if that's what it takes to develop your capacities to the point where you can make a real contribution. As usual, I want to point to Richard Hamming's "You and Your Research": http://www.cs.virginia.edu/~robins/YouAndYourResearch.html