Timing

Walked off the train and out the station at just the right time (and angle) to catch a nice sunset.

Timing is one of the most important skills I think someone can have, both in photography and life. You might have the perfect settings and shot, or the perfect thing to say or do, but if you're just a little early or a little late, it's all worthless. Would that we all could have perfect timing. Life would run so much more smoothly.