leave their bag on the window seat while they sit in the aisle seat.
AND pretend not to notice you standing up.
We all want two seats and only buy one ticket but y'know- shit happens. There's luggage racks- use them.
Rather than politely agree to move when asked why not go the extra millimetre and simply make the seat available if the train is full- do you think those people standing are doing it for giggles.
I'me fairly assertive (read: obstinate) about asking, but all over the country 1000s of shy people are having to stand unnecessarily.
I appreciate this rant has been knocking about for decades- sorry.