||Some of the shittiest customers I encounter are those trying to return things. They treat you like you're a piece of shit, someone beneath them, because you're just a lowly retail employee & you're not letting them return the earrings they bought 8 months ago, wore the hell out of, never cleaned, and then suddenly decided they didn't like anymore.
Every time we do a return at my store we're required to get the customers name & address. I take down that information on the ones who are jerks & then later come home and register them on all kinds of ridiculous mailing lists, support groups, charities, whoever I think is going to send them the most, and embarrassing, junk in the mail. It's certainly not the most devious way I could potentially enact my revenge on them, but it's a little something that makes me feel better.