Pyotr Petrovitch walked down the street and pondering. Stood around the warm spring weather, but his mood was heavy. Its depressing that something indefinite, vague, but no less strong. It seems that today there was a lot of good little things - he successfully joked at work, eat delicious, and the evening was paid. However, there were nasty little things - the morning slipped and almost fell, dropped his money on the bus at the store forgot to buy milk. Pyotr Petrovich knew which gives the value of a nonsense, allowing it to influence their own state, and this irritated even more. He had a vague feeling that it's not necessarily that he is able to create for itself a positive attitude. But how? Is it possible to change their response, their habits? Is it not natural for a man upset over nothing? Apparently, people are doomed to experience certain emotions, and they can not choose? Or is it possible? What if there are ways Control your mood, it just does not know? After all, no wonder there is a whole science - psychology. Maybe he just did not use those "levers" and "button", what could I use? Or rather to use - but against itself? And he brought the dark shades in his own state?