This made me think about dog bites. I've been bitten by a Dalmation (on the back of my neck as he was trying to mount me - I was about 10, running through his backyard - with his owner), scratched down my face by a lab (it was an accident but I was young, barely missed causing real damage to my eyes, this one scared me a lot), a scottie (on my forehead and my arm!! the dog lunged for my forehead and the owner said "oh no, he's nice, he wasn't being mean, just pet him" - then my arm! LOL that was stupid of me), and a miniature schnauzer (mine, he was having a panic attack - note to self: the appropriate reaction is NOT to clutch them to you and try to calm them with soft words - he bit my lip - that was not nice)
so.. I really don't know why larger dogs scare me, seems I'm split with my bites.
eta; large dogs that I don't know - ones I know, I'm fine with