In this story, a man gets irritated by someone he encounters, and kills them, easily (perhaps just by wishing them dead). It turns out that he is being rehabilitated for his violent tendencies - if he can make it through a year of simulated life without killing anyone, he gets released, but when he kills someone, he is sent back to January 1 to start all over again. This guy has been stuck in early January for many iterations, but as the story progresses, he meets a woman (I think) who is in the same process, and together they learn to suppress their desire to kill.
A man is in rehabilitation for causing a death after losing his temper while driving. He is in a computer simulation where he has to live “ordinary” life for a year. He can kill everyone else in a simulation just by making a wish. And almost everyone else tends to be very irritating. Only catch is that if he kills someone, he must relive that day again. And again. Fairly good and interesting story. Only: you are living in a world where you can do anything you want, and the only consequence is that you have to relive that day. And that is considered as a punishment?