There's a debate about whether Zimmerman should have been carrying

[The Magistrate]

75. Personally, Sir, Weaponry Was Not Necessary for Me To Be Exceedingly Dangerous

And awareness that one can do serious harm, and some practice in having actually done it, does indeed condition how one looks at people and situations.

If you think your own mental state, and physical state, does not alter how you perceive the world around you, you are either not very perceptive, or not very honest with your self.

It is an element of human nature that what people think they can do something about, they will look at more closely than they do things they feel can do nothing about. A person aware he is in possession of deadly force will be aware he can do more about a certain class of situations or behaviors, and further, will know that rapidity of action may be an important factor in whether a thing goes of well or ends very poorly.

And this is quite separate from whether the person is actually looking for a chance to do something, which you would be incautious to try and deny is fairly common among the hard-core of 'gotta have my gun on me' enthusiasts.