Aside from the annoyed part, I actually will block those from behind because I have been stuck in a window before where the inconsiderate db's in the rows behind pushed forward, nor allowing those inside the row to exit.

If I sit aisle, I will get up, grab my crap, and leave as much space for seat mates to push in to the aisle. If I know which bag they had, I will offer to pull it down.

I think this is common courtesy.

In my view it is rude to be in the aisle and not have the backs of the window/middle folks in your row. (Unless they were pure ares during the flight-which has happened )