One interaction that could be enhanced or augmented is the action of saying goodbye or hello (aka waving). I imagine some sort of exaggerated movement of the hand or other part of the body signaling a wave as a hello or goodbye.
Another interaction that could be enhanced is the act of carrying items. Based on the amount or weight of things you are carrying would create a change in the appearance of your sleeves or other wearable item.
I can imagine shoes that will signal to you via color change, inflation, loss of weight, etc. once you have reached a desired number of steps or distance traveled.