Rottweiler. Once.

He lived down our old street and his owner was walking him and i asked if i could pet him and told him i had a Rott too, he said yes then he bit me hard and i bled, it wasnt really a big deal but i was so shaken by it i started to cry.

I would not let a stranger pet Face, but i thought since he said yes that it was ok.
Guess not.