I've learned to be aware of my surroundings and not present like a mark. Same with my wife.
I'm a fire inspector/arson investigator. You'd think I'd be armed anyway, but remember, I live in California. They told us we have the police to protect us if we need help. I have the power of arrest, search and seizure and I'm a peace officer according to the penal code but I can't even carry spray, knives, or kubotan, much less a firearm. Anyway, I had an assignment for about two and half years on a task force for building and code compliance in our gang neighborhoods. A sideline of this detail was providing intelligence to the police gang task force and the gang prevention unit. I learned quick to keep my head on a swivel. I started carrying a Surefiire flashlight and a stick that I used to test smoke detectors and exit light buttons. I also started carrying one big heavy metal clipboard. My "civilian" partners thought I was nuts. I mean, there we were, causing gang members to be evicted from their homes, and "mysteriously" gang task force members would start watching the area and arresting people. It didn't take long for us to become very unpopular.
From that experience I've carried a lot of new knowledge about what is going on around me. I used to be blissfully unaware about what goes on in the tweaker/mexican gang/illegal immigrant world. Not anymore. That stuff is all around us in my neighborhood and I didn't see it before...I see it now.
I don't have any gun or hunting stickers on my truck, I dress normally so I don't stand out as having money, and while me and the wife are out doing stuff I'm on 360 degree watch. I developed that look that Frisco mentions...you don't want to mess with me and I know who you are. But I also developed the ability to recognize and steer clear of certain people and possible scenarios and situations without even being noticed. That is what I'm proud to have developed since I can't even defend myself in this state.