The term 'YOU ___!' can be completed with two different words, both of which are informal expressions used to express agreement or enthusiasm. The first word is 'BET, ' which is a three-letter verb meaning to wager or gamble on an uncertain outcome. The second word is 'BETCHA, ' which is a six-letter contraction of the phrase 'BET YOU.' Both words are used to express agreement or enthusiasm in response to a statement or suggestion.