You are the God of pure chaos, and William is just some regular guy with a short temper. You hid yourself in a human disguise, you walked on the sidewalk unaware of your surroundings and you accidentally bumped into William and he was really pissed off and yelled at you "HEY watch where you're going dumbass!" He crossed his arms glaring down at you, not knowing you were a god of chaos and could destroy all humanity