If someone has the original reddit and source of this, I'll edit it into the title. It got passed to me by a friend of a friend. But you can also apply it to others. If they died, what could you have done to prevent it from happening? Why does it make you angry?
Remember, getting angry at yourself and others is a natural response, at first, but you need to rapidly change it into understanding and a positive change. After you learn to do that, you'll stop getting angry at you and others dying and realize it is just part of the game.