My old roommate and his girlfriend (who pretty much became my roommate as well) were assholes. This is how I got my revenge on an ongoing basis and eventually got them to move out. She didn't pay rent, BTW, even after I pressed for it. So I took a brush and put a light coat of whole milk on the armpits of their coats and the insides of their shoes to make them stink. I'd pour rubbing alcohol into their vase of fresh flowers to make them wilt faster. I would cut a few threads here and there, and pluck buttons from clothes whenever they were left in the dryer. I ordered bridal fashion and lingerie catalogs mailed here in his ex-girlfriend's name. I tore small holes in their freezer bags to make their food get freezer burn. I had a remote kill switch on the WiFi. Two months later, they moved out. Then I got a raise and now I don't even need a roommate! I love it!—Anonymous