I've been bitten a couple of times. Once, while not bitten, I was being charged over and over by a large female pit bull. I made like I was going to hit her on the nose with the box, and she'd back off, then charge again. Owner opened front door, watched us going around in circles for about 15 seconds, then told me to stop teasing her dog! Told her if she wanted her pkg she'd better get the dog off of me.
While in AZ we had a courier at sister station get attacked by a large dog that ripped away the front of his shorts. Sr mgr met him at emergency room, threw his suit coat around him. Ended up getting 4 stitches in a testicle. Ouch!
Once went up to a mobile home in a really rough area that had four large pit bulls staked out around yard. One I could tell was dangerous, the rest I ended up petting on the head. One scary looking man with prison tattoos on his chest opened the door after I knocked with a shocked look on his face. He said "Mister, I just want to know one thing. How the hell did you get past my dogs"? I smiled and said I get along well with most dogs. He just gave me a very weird look.