I agree with AtlLaw. I could be mean, but I'm a lot older, a bit slower, a tad softer, but hopefully a lot wiser than I was years ago.
For me, the last thing I want to do is let some punks get their hands on me. At that point, the odd's are in their favor. Might be different if I was a martial artist, but I'm a street brawler. And I ain't running away either, because I don't want to turn my back on them. They'd probably catch me and I'll really be screwed because now I'm out of breath.
Remember, most punks and predators go after soft targets...those they think they can easily take down. Your best bet is to not look vulnerable and let them know it'll cost them more than it's worth to mess with you. Basically, discourage them to go pick on someone else.
So if it's obvious there's a showdown coming, I want to keep them beyond arm's length. I'll use my brains, my courage, and whatever weapons are at my disposal to discourage them from messing with me.
If I can't tell for sure, then I'll keep my hand on my gun and try to alter my path. If they attack suddenly, I'm shooting first. If I wind up in court, I'm an old man, being overpowered by several violent and healthy youths, and was dreadfully afraid for my life.