you better

Same as "you should", though it can be use for any subject (I, he, she, we, it, they). Implies advice or warning. Common in the southern US, this phrase has been shortened down from: You would be better off if you... You would be better to ... You'd be better... You'd better... You better... Sometimes as a threat, a person will mistakingly say "you had better...", but the uncontracted version is "would" not "had".