I've been bitten once by a dog, when I was 12 or so. A big dog too. I've never been afraid of them, not before and not since. (I didn't even tell my mother I had been bitten, she found out a week after the fact
Didn't think it serious, while I had three nice puncture marks in my thigh).
We always had dogs. And all of them were well-behaved. My last dog (I've moved on to cats now, though, I'd love to get a dog again...) was a rather dominant one. She was very protective of me (she once even threw herself between a me and a dog that was at least thrice her size. My mother and I were the only one that could take care of the bite marks...). Whenever kids would want to pet her, I'd always tell them off (she disliked kids, of any breed... they do say dogs will look like their owner
)
I would never say: Oh she'll not bite. Any dog can bite, for any reason, simply because she thinks she's cornered. Especially if the one coming towards the dog is a stranger. Dogs are still protective, no matter their breed and upbringing. Corner them, and they'll react.