ANSWER: Yeah right. Don't overestimate yourself dude.
Criminals are far better prepared than you think. They sit around all the time studying UFC and YouTube so that they can pick out the best ways to GET THE JUMP on an average guy like you in a fight.
A lot of them are pretty darn good at it too, and if they know more than you do they can take your money, have their way with your wife (while you watch), or take your life and hers.
If you want to win you need to be trained. Period.
Anything else is just an excuse.