Oh, you reminded me, bibbity, of a summer day in 2009, while walking through a park, a yob slob youth told his girl'friend' she was a "fucking bitch" and I told him to apologise, first to her, and as a secondary reason, because there were youngsters running around playing with a ball.
He initially refused, with a silly 'you wanker' attitude, and I then said to his girlfriend "You can do better than spend time with a loser like this"(looking down my nose at him).
She smiled, he went red, and I expected him to get a bit nasty. I think he might have wanted to "have a go" and while I wear glasses (but photochromic, so just looked like sunglasses) and would never be described as 'all muscle' I think he knew that he might get away with a punch or kick, but if I came down on him, my 15+ stone would definitely cause him some pain.
He apologised to his girlfriend, which she accepted, and as I turned to walk away, I saw him giving me a V sign, at which point I did grab his arm, and twisted firmly. He looked like he might have cried, and I said that I take no cheek from youngsters like him, and to get out of my sight.
It wasn't anything serious, but for all he knew I might have been trained in the military (I was considering the navy at one stage). I am no violent menace, and find saying something very quietly so one is not drawing attention to a threat can be far more effective than actually using violence, which could end up in court.