In a recent op ed in the New York Times, Arthur C. Brooks tells an interesting story. He spoke not long ago at a Mormon university, Brigham Young, and his hosts gave him all sorts of BYU branded paraphernalia, including a very nice briefcase with the school's name on it. At first, he says, as a non-Morman and not a graduate of the school, he hesitated carrying it, but it was really nice, and so he finally started to travel with it. And something strange happened. Carrying around the name of a Mormon school, he began to reflect on the virtues that Mormons are known for, like friendliness and courtesy. And, without ever deciding to, he found himself becoming more friendly and courteous, and helpful to people in airports. He came to realize that he had started acting like the people who gave him the briefcase.  He even felt happier, he says, "almost like magic." And, he writes:

But it wasn’t magic. Psychologists study a phenomenon called “moral elevation,” an emotional state that leads us to act virtuously when exposed to the virtue of others. In experiments, participants who are brought face to face with others’ gratitude or giving behavior are more likely to display those virtues themselves.

He's right. Exposure is morally contagious. What we're associated with, or around a lot, gets under our skin, and into our personalities. There's a bunch of research showing that we become like the people we're around, in a good or bad way. Hang out with cheerful, friendly, optimistic and upbeat people, and you'll tend to become one of them. Hang out with grumps, and you'll end up in the dumps. 

There's an easy solution. Dump the grump. Ok, not the cat, but you know what I mean. Read better stuff. Take care what you watch continually on tv. As a result, you may not only act better, but feel better, "almost like magic."