I'm pretty sure I could do some damage on most people since I've done kick boxing for a couple of years.
But still, you never know what happens in the end. One thing I've learned over the years is never to underestimate your opponent, ever. During sparring I beat guys that were bigger than me and I got my ass kicked by chicks that looked cute, petite and harmless. Also, always remember there will be always someone out there who is tougher/crazier than you. Haven't gotten into a real fight for over 10 years though. I always avoid that shit, because people carry knives or can grab a glass and shove it into your face n shit.