N American long time resident in UK here:
Negs-
Brits thinking they are politer than everyone else. That would be no. They are about as polite as Americans (taking into account that New York and London are about the same.) Brits can be extraordinarily impolite, and if you (as I sometimes do) get fed up & point it out to them, you get accused of being rude!
Class obsessed. This is not the same as “status” obsessed, which some Americans, as well as other cultures, can be.
Introversion. - I remember going to business meetings & endlessly meeting the same type: limp, damp handshake, mumbled name, no eye contact. He would not be allowed out of the office to represent a company in the US! This has somewhat improved.
School obsession -so boring. Brits do not seem to understand that achievement is largely driven by family values - too much responsibility placed on schools-teachers for children’s outcomes- manners, fitness, learning.
Queues - the U S convention, imperfect, but usually works, is to form a mass in front of, say, ice cream counter. Queue people Note who is in front of them, then step forward when server says, who’s next. If someone else steps in front, you say, excuse me, but I believe I was next, & other person will usually retreat. If he does not, the whole crowd will give him the evil eye. This system requires interaction with other humans, hence the likely reason Brits prefer their long, snakey, inefficient queues.
Buying & selling houses - don’t get me started! Must be the worst system on the planet.
Never had the dishwashing issue myself.
Hatred of bartering - I had a bizarre experience where I was in Morocco on a spa holiday & went with a group of MC women to the souk in Marrakesh. We all wanted scarves, & relishing bartering (I used to live in Mexico, so rather good at it) began to do so, when stopped by horrified Englishwomen, who wanted absolutely nothing to do with such an awful practice & would rather pay full price, thank you very much - just bizarre!
Pluses - English summers, the best; Brits party way better than Yanks. Great cheese, bread, meats ( tho fruit & veg in France is tops). Great fine art, rock and roll, music generally, stately homes, architecture, town planning, countryside. Eloquence & humour. System of justice, animal welfare, tolerance (mostly).
My favourite Brit community is equestrians , incredibly helpful, supportive ( high degree of sportsmanship even if you are competing with one another, not like that in US)
Not going anywhere, me, just learned to dive & dodge around bits I don’t like.