Anatomy lessons

People have shoulders
Some of the cars in the New York City subway system were designed with "bucket" seats. Unfortunately, the designers failed to take into account the fact that people are wide across the top, as well as across the bottom, and the "bucket" seats prevent us from sliding sideways to make the necessary accommodations. The upshot is that we end up literally rubbing shoulders with total strangers, whether we want to or not. This is a case of quite literally putting the squeeze on us riders.

Yes, men and women are different
Let's just say that it has been tactfully explained to me that men often find it uncomfortable to put their knees too close together. But some guys take "getting some air down there" to an extreme. I can't tell you how many times I've felt, when riding the subway, that if I put my knees any closer together, they'd get glued to one another. Sometimes women simply conclude that expecting to be left enough room to sit in some reasonable semblance of comfort is a lost cause, and choose to give up their seats and/or stand for the rest of the trip.

Ah, the joys of subway riding. On the plus side, at least we don't have to pay for gas.