Passengers on LHCS, please by all means when boarding or leaving a train just leave the door open behind you, the guard will really appreciate having to run up and down the platform closing them.
Holiday makers on Liverpool Lime Street to MIA services, leave your bags blocking the doors so that nobody can get on or off the train, and then when the driver asks you to move them to the appropriate area look at him confused and let him move them himself, its not as if he has a train to drive or anything.
Man on railtour that I guarded recently, I've put signs asking you not to sit on that seat for the good of my health, not because its broken and you could be injured or anything. Then when I ask you (nicely) if you would like to move, bark "I'M FINE!" at me, I really enjoy being shouted at and will be happy for the rest of the day.
Woman who has left her phone on the train, run alongside whilst trying to open a door and jump on, causing me to pull the emergency brake, because its very sensible, won't result in injury or death and won't annoy the now delayed passengers!