Fun fact: I lived and traveled with my border collie I got since I was 16. Never leashed for my own sake (always lived in "the bad part of town" until I was 20-21. (Border collies aren't really dangerous, and it had been trained very well, never in the 9 years up to this point have I ever had trouble with it straying away).

One time when I was in the Midwest a lady a couple doors down had her husband drop dead. She had the sweetest German Shepard and I used to go over after work sometimes to talk to her and her husband, get some stories, exchange some. I loved that pair. Well one day when her husband died, her son was the only one home. He called the police, which sent EMTs to take away the husband. When they took away the husband, the dog witnessed and had developed a fear or grown adults because of the EMTs. So one day, I'm walking my BC, and I see the German Shepard start barking at me. No big deal, until I glance over and see the glass door is wide open.

I start to casually walk hoping to get away before it notices, and I glance back over and it isn't there. It's bolting through the fucking yard full speed. Glance to my right and my border collie is noping the FUCK out of there. Dog finally reaches me and just up to bite my face, upper chest, neck or whatever, and I instinctively throw up my left arm so he bites it instead. I bop it on the nose and it goes for a second blow, and I pump my knee into its chest. The dog literally rose like two feet and then fell down, and I BOLTED out of there, and onto the hood of my car, then unlocked it and scurried down and got in.

Also, instead of calling the police to get it put down I acknowledged the dog was just being a dog, so instead I called the lady and told her of the incident and helped pay for classes for it to get over it.