I got bitten by my friends lab pup a few years ago. It was my fault though, it was sleeping and I woke it up while petting it. There was one time when I was scootering and I stopped to glance at my watch, and looked to my side to see a snarling GSD, unleashed and on it's own just lieing down. I started scootering away and I looked back to see it chasing me. I started going really fast and it finally went away.