The positive thing about the French pharmacist Émile Coué has already been described: One should simply tirelessly talk about one's own well-being. Of course, that works the other way round too. You can use some learning techniques to condition yourself to see everything like the man with the picture.
The Pursuit of Unhappiness
What can we do daily against our possible happiness? After reading, you too will understand why you would like to slay the neighbor you asked for a hammer.