I thought this scene contained several interesting elements: buildings on both sides, wet, shiny, reflective pavements, light from the shop on the right, light in the sky in the distance, but even with the bus approaching, it might still be lacking something.
Then the lad in the black and white jacket walked into the scene, turned towards me with a double "thumbs up", and smiled.
His movement and reflection completed the picture, and all that was left to do was press the shutter.
I don't think I could have composed this, and I wasn't aware of him until he walked into the frame. Luckily, I was about to shoot anyway because, otherwise, I would likely have missed the shot.