Just saw a neighbour in passing in the street. He was walking his (huge, adult's waist height) dogs and I said hi to him. One of the two dogs barked, lunged/jumped up at me and tried to snap at me. I leapt back and the neighbour said "ooooo shhh shhhh" to the dag and "oh she doesn't like surprises!" To me. Admonishing ME for having said hi? No apology 
I was really shaken.
I'm a dog lover, & grew up with them and am not afraid of them generally but that gave me such a fright. Thought I was gonna get bitten for sure. I only said hello to their human. Didn't put a hand towards dog or owner. My SD is about the height of that dog and terrified of dogs larger than Jack Russell's generally. This would have made her actually poo her pants!
The same dog did the exact same thing at my DCs when we rounded a corner in the street and it came round from the other side which frightened them then too ... and again no apology just the kids being told not to frighten the dog!? They were only walking home.
The dogs are on harnesses and tough leads but it was School run time, lots of potential "surprises" for that dog, I don't know the politics of muzzles (I'm hella sure I'm about to learn them) but large dogs that snap and go for passers by surely ought to have some sort of safety net?