One thing I have learned over the years is not to be too quick to delete my pictures thinking that they are not quite up to scratch. In the past in order to save HD space I have deleted a bunch of pictures from a shoot only keeping the ones I thought were the best, but now I only delete the obvious failures such as missed focus or camera shake. Every month or so I go back to past pictures and it's surprising how many times I see a shot and think how did I miss this one.
The shot above is a perfect example. I found this one today when going through some pictures I took last year. At the time I thought the colours were not quite right and it had too much clutter in the foreground, probably my attention was on another picture when I imported them into Lightroom. But today when I saw it I thought it would look nice cropped as a panorama and converted to mono with a bit of split toning. It's also a fact that as my Lightroom and Photoshop skills improve I see potential in shots that I simply could not see in the past.
So keep your finger off the delete button and save your shots for a rainy day.