I like a few things from M&S but ye gods, people are rude in there.
The staff are normally obliging, and M&S deserve their no-quibble reputation as far as I can see.
It's the CUSTOMERS that wind me up. Going into M&S seems to put some people into an entitlement trance in which they can no longer register the presence or needs of others.
They block aisles. They rudely reach across and snap through the hangers on the rail I'm looking at.
They stand for an hour with a packet of mints, eyeing up another packet of mints suspiciously and not recognising that anyone else might want some mints this decade.
They walk in strange, random trajectories that are impossible to predict/overtake. They dither through the doors chatting in twos and threes, and don't bother to look behind them to see if it will slam in anyone's face.
I usually go into M&S with my Grandma and she turns from quite a kindly lady into someone who won't change her course of direction for people on crutches, or makes free to read an ingredients list to herself at the back of a queue so no-one can tell if she's queuing or not.