Do you know, I think this might be a topic that people can broadly agree upon... but I've been wrong before.

To the list above I'd add some more examples:-
- the person who sits in the aisle seat and leave the window seat empty and harumph when someone wants to sit down, making great play of moving their legs a tiny bit rather than just moving to the inside or standing up to get out of the way
- people with bikes who leave them strewn across the doorway (though Southern really ought to do more to make the trains bike and standing-person friendly)
- the ubiquitous badly-insulated-headphone/too-loud-mp3 listener
- the person who comes and stands directly in front of you and the yellow line when you've been stood patiently waiting for a train for 10 mins or more
- those unfortunates who get off the train, stop directly in front of the doors looking around and pondering where they are going to go to next. I know they might be disoriented, but really, take a few steps and let everyone else off, please.

Oh, that feels much better...