If you assume that "rationality is a mask," a mask that all human beings wear, then when the mask falls and humans do something irrational, it's not so shocking or surprising. I mean, I guess it is always shocking or surprising when supposedly "rational" people, who we think we know, do something "irrational," but I think it's actually part of the human thing. So anything you can imagine, can and will be done. Even those things that you can't imagine being done by people you think you know. People will do those irrational things. And you will be shocked and surprised. Sometimes you'll even be shocked and surprised by some of things you do too. I go with that idea that we are all capable of the best and the worst.
So when you read that an olympic hero shot his girlfriend, or that 20,000 of the 30,000 gun deaths in 2010 were suicides, you might be shocked or surprised, but really you probably shouldn't be. That kind of stuff is almost predictable. The irrational is with us always. And you realize when we talk about gun control there is a huge blind spot in the conversation. We like to pretend that there are "safe" and rational reasons to have guns in our culture. But that's probably not true. And the people who are attracted to guns are probably not as "mentally healthy" as they pretend to be.
The "good guy" with a gun, is just as likely to be the "bad guy" with a gun... same guy, same gun...