Someone once told me the difference between cops and fireman (and why one group tends to be d*cks, while the other group tends to be heroes) is that when something bad happens to a cop, he/she can take it out on the next person, and the next person, and the next person after that. When something goes wrong at a fire, all they can do is try to be better next time.
Some things take a while to get right, you have to go back and do it again and again, and again. All you can do is keep on that path and keep working on it. Some of my photos, like the Custom House lights, I kept going back to and shooting over and over again till I got the shot I liked.
But most of life is more like my job - one night only. And if you don't get it right, you don't get to redo it. All you can do is try to do better next time, and not sweat it in-between.