Okay, here are my bits, with all of my experience (2 weeks- wow!)
-I think it's funny that the UK has American commercials- with dubbed English accents! On some of them, the dubbing is Godzilla-style, i.e. mouth moving without words coming out. I suppose it saves money.
-Just a guess, but maybe the dishes are not rinsed because of the non-mixer taps? I have to admit, it is harder to rinse a dish in a small sink with separate taps. I still do it, but it is a bit of a trick.
-Hmmm...I haven't had (or seen) a sandwich with butter yet. But I've only had a ciabatta and seen readymades.
-I must live in London-land which, like many big cities, is apart from the normal world. My grocery shops are 24 hours (except Sunday evenings), My bathroom is basically the same as I expected, etc. Only it's a bath, no shower. But it's cool. It's a nice bathroom

-Vest=waistcoat, and vest=sleeveless shirt . I actually knew that, but slipped into my Americanism with a poor harried shop guy.
"How much is that vest?"
(grabs blouse)
"This?"
"No, the vest. Er- I mean, waistcoat!"

I'm really glad I had this list. There were about 99% less suprises than there would of been otherwise. Thank you to all who posted. I'm glad I wasn't at the supermarket, staring at the checker, wondering, "what is taking so long with my bags?"