check yourself before you wreck yourself

slang You need to reconsider the way you are speaking or acting before you end up causing real trouble for yourself. Primarily heard in US. Yo, are you talking trash about my girl? You better check yourself before you wreck yourself, fool. A: "I'm going to go in there and give the boss a piece of my mind. He can't treat us like this!" B: "Hey, you're going to get yourself fired! Check yourself before you wreck yourself, Tom." I'm telling you this as a friend—you've been drinking way too much. You really need to check yourself before you wreck yourself.