A while back I was a regular at the blackjack table in a seedy bar that was nearby my apartment. One night I had a good buzz working and let a comment slip, at a volume I didn't think anyone else would hear, about a drunk like the figurative one in this thread. Unfortunately the beer had disabled that little mechanism between brain and mouth, that filter of content and volume that keeps inner monologue on the inside, and the guy heard what I said.
He came up, very close, and started having words with me. Specifically he told me that it was on when I walked out the door, then he walked away.
Short-term solution: As soon as he came up to me I tried to be friendly - "Hey man, I'm just messing around. How bout I get you something do drink." He wasn't interested.
Back-up short-term solution: I'm generally a guy that isn't hard to get along with. That night it came back to me in the form of a big favor. When I left, one other regular and one of the blackjack dealers saved me from possible legal trouble and a probable ass-kicking and walked toward the door with me. When the drunk saw me walk out with two other people he decided to find easier prey. He was later removed from the bar for actually starting a fight with someone else.
Long-term solution: I still go to that bar occasionally, but never on weekends and never alone. I still like the atmosphere (on quiet nights), the "by name" service, and the prices are still in my range.
Failing either short-term solution, I probably would have fallen back on a self-defense moved learned in the army that should have proven semi-effective. It involves the gonads and is informally referred to as the "grab, twist, and pull." Like many here, I've spent some time learning martial arts, but that night as I was heading for the door, the only moves my mind kept reviewing in case they were needed were the most simple ones, like the one above, or how the pen in my pocket could be used most effectively.
It's bears repeating again - if you need a weapon to be there, it's best just not to go. This was a rare circumstance at this place. Additionally, I made myself more conspicuous than I should have. In the end, I got lucky. Best of all, I learned from it and it could have been a much harsher lesson.