After Helping My Roommate Get Six-Pack Abs, He Turned on Me

My roommate was 185 centimeters tall and weighed less than 50 kilograms. He begged me to help him build muscle, promising to give me 10,000 yuan once he had six-pack abs. I spent a whole year training him and making him nutritious meals. At last, my roommate turned into a hunk. But after he got his six-pack, he refused to pay up. [My success at building muscle was all down to my own willpower. What the hell does it have to do with you?!]