To tell the truth I haven't really played any really bad sports (luckily). In terms of tactics though, I have played some complete idiots. My main opponent is a generally nice guy but strategy wise, he's a complete retard. Examples include, "my Callidus assasin is assaulting your seer council" (with a wraithlord within 4"), "my bog standard IG troops will assault that almost completely upgraded scorpion squad," and even, "my super expensive VDR flyer that takes up about half my army is going to fly right over those two AA upgraded falcons, D*mn! He got shot down!"