When entering a store or supermarket to do groceries, people generally do not pay attention to the automatic doors. They are a common sight nowadays and people are used to the doors working. They provide extra comfort and people find them convenient, as they open when you approach with a heavy loaded chart and close behind you. No extra action is required on the part of the person entering/exiting the building. But it is not something you realize is working unless your chart bumps into the door, or when they do not open fast enough.