I think it's perpetuated by the "team" that is on at any given time. It's easier for a group to all behave unplesently that for one individual to behave nicely with some manners in front of them. It is a case of poor CRM and poor Team Leader etc.
.....as an example, T5 transfer area has now gone to a "2 at a time" system placing the trays on the conveyors. I was yelled at for moving forward to make it 3 at the tray area. Well sorry, last week it was "3 at a time", in that area.
But it's not just in the UK.....i.e. JFK sucks, Newark is great, Frankfurt sucks, Zurich is great, and on and on and on.