Elevator Diffusion 

The phenomenon in which people evenly distribute themselves in an elevator, especially after people get on or off said elevator.

Failure to do so will result in very awkward situations.

John: The elevator's stopped, time for elevator diffusion!

Kate: Why is this random standing right next to me?
John: Hey buddy! Follow elevator diffusion!
Random: Sorry, man

Elevator Diffusion by relativity13 April 5, 2011