Of course that happens often to me. I look back on something I photographed last year, or last month and think, "What was I thinking? I could have done a much better job.
These images focus on edges. The lighting I had this particular day lent itself well to strong contrast: bright highlights and dark shadows.
These last two images are my favorites (and I think the best) from the whole day. I love the mystery of them. They're abstract, and yet still have a rock-like quality to them.