I haven't been doing a martial art for very long. I have had cause to defend myself on three occasions in my life, and on all of those occasions I did OK. I'm female, and each case was a single, male attacker, unarmed. Two of the occasions were muggers (I went to college in a rough area). They were expecting easy prey, and when they grabbed me I reflexively flailed / kneed them, or hit them over the head with a very heavy bag of college books. Then ran away as fast as possible (I used to run competitively, so was fast, and could run for longer than most "normal" people). I now live in a much nicer area, and don't anticipate any more trouble, but if I ever did have cause to defend myself, I think that right now I'd probably fall back to the same crazed / shock the person by being a lunatic defence. My style of Karate does involve sparing, and I'm finding that when I'm up against men my short stature means that if I'm close enough to hit them (even with a kick), they're close enough to grab me. I have learned a lot about blocking incoming hits, but at my current level of experience (very low), I don't think I would rely on anything I've learned in the dojo as a way to end a fight.