Well, I've had people I'd judge as potential threats turn around and leave just at the sight of my pistol. I didn't have to put my hand on it or anything else. It was just sitting there in it's holster for all the world to see. They saw it, and they saw that I knew they were where they were. They left. This has not happened often, but it has happened more than once.
I once had a "potential threat" approach to within 10 feet, and ask me what I'd do if he came at me. At the time I'd just left a store, and had bags in both hands. My response was "if you force me to drop one or both of my bags to defend myself, it will turn into a bad day for both of us."
Now, there's no guarantee that he would have been so stupid as to ask that question if I'd been carrying concealed. But I have to wonder if he would have just plain attacked me, without asking first, had I been CCing. That is another situation we could "what if" to do death. All I know is, since I've been OCing, I've been in a lot fewer tense situations, or in places where I'd wonder if this was gonna be the day.