I didn't have any specific expectations, A (other than meeting men with names such as Alastair, Nigel, Ian, Percy--names that would get you beaten up by guys in the States). Just kidding.
In my case, I'd dated a couple of British men in the States, in between "serious" relationships--two from London, one from a fairly upscale Manchester suburb (or is that an oxymoron?). I hate to say, but none of the three had much positive to say about the UK--hence, they were in the States. The one from Manchester even drunkenly told me on the phone one night (he was in the midst of divorcing an American woman) that not only had he slept with her best friend, but the only reason he'd married her to begin with was to get the proverbial green card. Which he did. He was shocked when I mentioned the conversation the next day--he wasn't someone who was open about his private life, to put it mildly--but conceded it was true. His family wasn't that close--his parents still live in the Manchester suburb, one of his two brothers lives in London, and the other in Australia.
I had been an Anglophile as far as British humor and classic rock went. Before I actually met my future husband face to face in the disaster area known as Heathrow's Terminal 3, we had exchanged emails, spent hours on Yahoo IM, and even more hours on the phone. He was very cynical about Britain (still is), and although he'd never been to the States, he told me I'd probably be in for a shock when I visited here. I got here on a night flight, so there wasn't much countryside to see driving from Heathrow to Brighton. After the initial tears of joy at the airport, I just soaked it all in--the left-side-of-the-road driving, especially after we got off the main thoroughfares and onto the sidestreets here. At first, it was like a vacation. Although, at the time, it was the beginning of June 2000, he had only BBC 1, BBC 2, and channels 3 and 4 on TV, so any given weekend, your choice was: soccer, soccer, horse showmanship, soccer.
For some reason, I didn't think the UK would have big supermarkets like the ones in the States, until we first went grocery shopping together. And then, fellow vegetarians that he and I were at the time, it was clear that he knew his way around the stores as much as I did. We'd have a laugh--people say Americans don't get irony/don't find the comical. In this one Tesco we went to, as soon as you walked in the store, the first thing you saw was a refrigerated display of fertilizer/cow manure, in the same unit as whole chickens. "You know, Andrew, when I think of manure to help my garden grow, I also immediately think of whole roasting chickens.." Then there was the glove display next to frozen pizzas.)
Joking aside, I think the biggest shock to me then (and somewhat more understandably now), was the viciousness about Americans, their culture, their accent(s), etc., here. Most Americans are aware that we're disliked abroad. But moving here and hearing just the nightly news and it's leanings, not to mention comedians, etc., was at first very shocking, then hurtful, then defensive-anger inducing. Yes, our president's an idiot (and that's just one opinion), but to realize just how much our supposed closest ally put us down was far and away the biggest surprise.
In the States, at WORST, you might hear (and very rarely) a comedian joke about the British along the lines of "Jolly good, then." But Americans have an incredible amount of respect for the British, one that's obviously not returned. That was the ONLY thing I didn't foresee. I can't speak for everyone, though.