The redheaded dude comes into my car (crossing from another car in the train while it's in motion! such a rebel) and passes behind me. The car isn't crowded, but I move my bag out of his way anyway, and he passes by with a determined look on his face without even a glance in my direction. Being a large person, and somewhat timid growing up, makes me extra-self-conscious of the space I take up.
Tonight, when I go to see a rock concert, I'll be worried about standing in front of people, worried that these short people whom I'll never see again will hate me for blocking their view, and they will take my awkwardness and low-self-esteem for politeness.