I'm not sure how useful it is to pass judgment over whether other people are wasting their time. If I'm doing something that's fulfilling to me, is that really a waste?

Besides, we really don't need most people to spend their time feeding the homeless or building shelters. It takes money, not work, to feed and house people. Our economy can easily sustain enough food for everyone and enough homes for everyone without anyone (including poor people) having to work any harder.

The fact that we're not feeding and housing everyone isn't really a reflection of how hard we're working.