I have some similar habits. I also always choose a seat in a restaurant that gives me the best tactical view I can get from that table. I prefer if I can see the door and the cashier - the two places I judge most likely for something to happen in most restaurants. I also prefer the aisle seat on a airplane, because I'd have some reasonable access to anyone causing trouble.When in a crowded bar, I would always walk through the throngs of drunken people with one hand on my chest, as if I were constantly scratching it. This is because I did not want my hands to be both pinned to my sides if some alpha male approached me to start something. It might sound silly, but there was actually a time where I deflected someone's attempt to give me a one-handed shove. By the time the deflection was over, I had my other hand up...and they reconsidered taking it any further.