Why?

Why do people spend millions and upon millions of dollars not to benifet themselves. The author of "What Should a Billionaire Give - and What Should You?" seems to belive in philanthropy. She talks about how Bill Gates and Warren Buffen are giving billons of dollars to charity. When I think why, a reason comes up in my head. If you give to charity than you get a tax break. That might be a reason to give. The auther also ask us what we should give. I say nobody should give it to people who don't desrive it, but it's really hard to find out who desrives money and who doesn't. Some billonares don't desireve what they have.