Those "Companions" and "Quest NPC's" wandering the wilderness, I've at least mistaken 2 or three for bandits and shot them. How many times has this happened to others I wonder? In a world so hostile, its hard to take the chance to walk up and say hello when most things want to kill you. I find with harder NPC's surprise is everything.
Quite a few times, my character isn't built for close combat so if I can't get close enough to stab them in the back I have to shoot them from afar. That ocassionally means that you're putting an arrow in someone who had no hostile intentions
I don't surprise attack anyone unless I absolutely know they're an enemy. However I find it extremely annoying having to be in someone's face before they decide they should kill me or not. -_- You would think even 10 feet away they would decide but no, only when I'm practically kissing them.
I've taken out quite a few mercs by accident, but I attacked a few travilers on purpose, luckily for them I spare the woman, my faithful companions on the other hand don't have the same level of honor I have.
been a couple of times that Iv killed a stormcloak soldier or Legion soldier only to have everybody turn on me. Not my fault he stepped in front of my power attack.