You should never forget these letdowns because they were avoidable. The writing was on the wall and there are lessons to be learned from such mistakes.
Not all of these players were first-round picks or even early picks expected to be studs, but they have all fallen short of expectations to a drastic level and something about their performance did not just lack a positive impact on your team, but likely brought a negative one.
Feel free to share your biggest letdowns in the comment box when you finish reading, as every owner has at least one horror story at year's end. If you don't, maybe you should avoid playing in 2013, as those things tend to catch up with you.