Do they? Most people I know are happy knowing that they're doing useful things. That happiness isn't impacted in any way by other people not doing useful things. In fact, if I'm honest, I'm considerably happier about living in a society with people who opt out of work to live on welfare supported by taxation than people who make huge sums of money but avoid tax themselves. I don't think I'm alone in that (although, that said, I live in Europe rather than the U.S., so that may make a difference.)