The perception of failure.
Last night, I decided to make a 4x5 paper negative of a lamp, yes you heard me right... a lamp. While everything seemed to be set up right, for some reason I was not getting the results I wanted. I ended going through five 4x5's and each one with the same results.
To be honest, when I looked at the negatives, I almost chalked them up as failures. luckily I kept one of the negatives and was surprised at how much detail I was able to pull from scan. If you don't know, a negative is the inversion of a positive image. In laymen terms, the whites are black and the blacks are white. Making a print of this inverted image makes a positive, the same is true when reversing or inverting an image in photoshop.
As you can see, the final image turned out pretty cool. In my mind, I pictured an amazingly lit photograph, but as you can see that didn't happen. Although that didn't happen, I think the lamp being less lit worked out better. My point is this, regardless of your feelings towards your photography, you should be proud of it, no matter what. Embrace your imperfections because in the end, those results might actually be better then that "perfect" image you first had in mind.