I was bitten by a Jack russell when I was about 5 (cant really remember how old I was) the dog was deaf and I went up behind it when it was eating, touched its back and it jumped round and bit my thump, took the nail clean off lol. My dad promptly kicked it down some stairs (dont worry it was fine). Was a nasty little dog, was so fat it was square and wouldnt let my nan sleep in the same bed as my grandad lol.
Never affected how I felt towards dogs though, not scared of them at all. I love em