My pet peeves on a busy London commute at the moment:
-People who get up (forcing you to move) ages before their actual stop. Unless you have mobility issues, lots of luggage or are on an absurdly busy train you don't need to be standing by the doors whilst you are still miles from your stop.
-If you are waiting for a train other than the next one arriving, then don't wait at the platform edge blocking people getting on and off the first train. Particularly if you then get the hump at people pushing past you.
Add your own rules and rants...