I am amazed by people who stand outside in front of the opening doors of trains and lifts knowing full well that the people inside will have to exit before they can enter. Obstructing the Exiters will only delay them, and the Enterers seem to be in such a rush that this is surely not in their best interests. What is astonishing is that this is a universal phenomenon. Explain!
I, too, have observed this phenomenon with trains but more rarely with lifts, and I think that suggests an explanation.
It is true that by obstructing people who are leaving the train, people may delay it by a few seconds.
A few seconds delay to everyone on the train is an appreciable social loss, but scarcely matters to the selfish individual in question.
True, a delay is a delay.
But you have misinterpreted what such people are aiming to do. They are not trying to hasten the departure of the train; they are trying to get a seat. That means being the first into the carriage just as seats are being vacated, which in turn means standing in front of the opening doors and generally getting in everybody’s way.
It is a classic prisoner’s dilemma: everyone would be better off if everyone hung back, but each individual does better for himself by pushing forward.
It is not surprising that this behaviour is more unusual when it comes to lifts. Lifts do not have seats, and usually have room to accommodate everyone who is waiting.
The behaviour you describe is selfish, but it is not irrational.
Also published at ft.com.