Something that came to mind happened a long time ago, maybe during high school or a bit after. I was shoveling our driveway after a heavy snow and noticed two or three kids acting like typical wise guys– throwing snowballs at passing cars, kicking snow I had shoveled back into our driveway, maybe some other stuff– some details are lost to the passage of time.
In any event, I happened to appear as these shenanigans were unfolding and either said something or gave them a look, though I am by no means an intimidating figure. Two of the kids ran off, but one kid stopped and actually helped repair the minor damage they had done. I told him, “Nice friends you have there,” or some such thing, and he eventually walked off.
I don’t know how brave it was, or if it was all that risky to get involved, but I felt good about the outcome, nonetheless.