Seld defense starts in the brain. It goes back to the old addage. If its predictable its preventable.

Thats one of the reasons I rarely drink much less drink to excess. I choose where I sit in reasturants and pay attention to my surroundings. I also look at every entrance an exit. I also watch people if someone is about to be stupid they usually broadcast it. I also trust my instinct. If someone just seems off they get greater scrutiny. Its ingrained from being on the job so long.