In my normal work as a commercial photographer, I'm used to taking control of a situation and optimizing it to produce the best image to fit my client's needs. I will place and pose subjects, spend time lighting the set and direct all aspects of the shoot. But sometimes, all the elements come together without changing a thing.
While shooting portraits at a nearby University, I noticed a student who found a quiet spot to study. Using a long lens so as not to bother him or draw attention to myself, which would have changed the dynamics of the shot, I took a few frames and moved on, happy that all the elements came together in one quiet moment.
Sometimes you get lucky and stumble upon a perfect scene. Canon 5D Mark III, 200mm lens, f2.8 at 1/125th sec. ISO 400.