when you're cutting nails and dragging clippers over their body, touching them
everywhere, etc you're bound to get bit by an irritated dog, along with not knowing if owners have socialized, trained, etc their dogs, that are going to try and bite you.
I've never gotten bit by a pit either. Cocker spaniels yes, Australian shepherds yes. Shihtzus, chihuahuas, Maltese, German Shepherd, lab, collie, mixed breeds, poodles etc. I've been bitten by all those and then some, but never a pit. And yes I have had a lot over the years as some don't want to deal with bathing or cutting their nails.
Funny that the supposedly "aggressive" breeds have never bitten me at work.