I never can understand this, especially when the train is crowded. There are just some people who must squeeze through the crowds, bump and walk all over people because they need to be standing right in front of the door before the train stops. It especially doesn't make sense at Embarcadero station because more than half the train needs to get off there anyways, so why not just go with the flow. A woman today, during mid-Transbay tube, started gathering her things, and step by step pushed her way through from the end of the train to the door. She squeezed herself to the front, forced everyone else to re-position to make room for her premature exit, and finally stood right in front of the door, about an inch from the glass. Sure, she was the first one out the door but she probably saved herself 5 seconds while inconveniencing at least 15 others.
Why do that?