The photograph I most regret not taking was this:
I was driving along Interstate 10 in Mississippi several years ago. The night before someone must have driven a car right into a big highway sign. One of the legs was completely mangled and the other was bent. The sign looked like it had come to life, started walking along the shoulder, and then froze mid-step as if the life had gone out of it as suddenly as it appeared. The highway department fixed the sign before I got around to photographing it.