People watching 101.
A simplistic composition framing the subjects in a very familiar setting. With the other side of the street cut off from our view and the subjects unaware of the photograph being taken, it constrains the subjects in the frame to this moment, on this side of the street and makes it more personal to us.
AKA, Super creep.
I get what you tried to do. It's a cool shot, but it would be great if shape formed by subjects would be more interesting. There is some kind of structure, but it needs to be more unique to be great.
Cool idea anyhow.