My pet peeve: The guy who comes into the gym with his sprawl shorts, tapout hoodie, and all the new and "cool" gear (without a mark on it, and that new leather smell)and as I explain "you need to come into the begginner class and learn the basics" he gives me a story about all his "buddies" who are MMA bad-asses that he has trained with, just not at a "gym". Then before he even breaks a sweat he explains "i wanna take a fight in the next couple months!".
This usually ends with the guy coming into the begginer class and getting jabed and leg kicked by a white collar father or chubby 15yr old..... At which point he explains "im a ground guy", Then sticks around for the BJJ class where he gets "tapped" several times in a row by a white belt, usually with the same submission 3-4 times (triangle, or kimura). Really, I swear this happens once a week!