Humor is zero sum?

I remarked to my friend Glenn yesterday that often the best humor is unfortunately at the expense of others. In fact, there's not really a symmetry to it -- you can't really make fun of someone in "positive" way because it probably means praising them indirectly. I suppose there's situational comedy as well - ala Seinfeld or something of that sort. But the biting satire that makes you wince inevitably involves someone else. You sort of feel bad for them, even as you smile or laugh. So it goes.