I used to have friend ("Used to, that is") who had a pet coon. Raised if from a hamster sized pup and it KNEW ME from that age, but the little bastard never liked me. Years later I showed up at their house, came in, hugs all around, looked to see what was cookin', and old Pepper (who now weighs about 40 pounds) comes up and grabs onto my leg, jumps a little and bites through my jeans into my leg just above the knee. I said "Ow"! He drops to the floor, jumps again, and bites again a little higher and I naturally put my fist right between his eyes and he took off. The friends wanted to know why I hit their coon. The puddle of blood forming on the floor next to my shoe didn't seem to phase them. That was the last visit I ever paid them.
I've been bitten by a lot of things, but that really hurt.