Sometimes, after shooting a photograph, an aspect of it which I didn't initially notice will stand out. For example, take a look at this photo from Monday night.
Initially, I was merely attempting to capture light trails. When I examined this image at home, I noticed not only was the trail captured, but it appeared to come out of the tiger's mouth!
Now let's peruse this image from yesterday night's shoot.
Look at the area where the couple is walking; do you notice anything other than the light trails? It isn't obvious at first, but the outline of a house is formed by the sidewalk, tree branches and trunks. Once again, this totally escaped me until I saw this photo at home.