When I am getting on a train, young people crowding around the doors to get on before you or anyone else. You are young. You can stand. What makes you think you deserve the best places to sit, or that other people come after you?
When I or anyone else is getting on a train with two pieces of luggage. People more liable to bitch about you getting in their way with your two pieces than to actually take initiative and HELP lift them up the 3 stairs.
In New York City, I can always count on someone - usually a man - to help me or anyone else to help get a heavy bag up or down the stairs to the subway. In Europe? Pfft! In fact, yesterday four men in their mid-late 20's stood by and watched me take my bags up the stairs of a bus. It was a woman my age who helped me.
ALWAYS HELP PEOPLE WITH LUGGAGE, especially if you don't have any of your own.