Probably door sensors doing 1: omg is there something next to me? 2: nope! ok..open door a bit more.. 3: goto 1 I imagine the door flying open and bo

Probably door sensors doing 1: omg is there something next to me? 2: nope! ok..open door a bit more.. 3: goto 1 I imagine the door flying open and bonking into things would be far more upsetting to customers than a slow one that you can open by hand to speed up the process.