Gotta ask: what's the point of trolls? What do they get by wasting their time and energy so they'd waste someone else's? Attention seeking much?

Ok, I get that it's the internet, everyone loves a good joke and so (tho most of theirs aren't good but I digress) but what's the point of going out of your way just to make someone spend time and energy on you, resulting in nothing? Because really, no one gets anything out of this. Is it for attention, do they feel somehow better, cleverer, like they're more important? Like saying "I'm right and you're wrong because I tricked you"?