I'm in the UK, and I work with a LOT of Americans already, so know this first hand:
- You fuckers are always in for a culture shock when you realise that everywhere isn't like London. You seem to either expect London or Harry Potter Land, but when you end up somewhere like Bristol, Leeds, or Birmingham the frame of reference just dies and you see the wheels turning in your head trying to make sense of it all.
- Weirdly, you seem to really like our supermarkets. They're a lot smaller than yours, meal deals are a novelty that never gets old, and paying the price on the tag is the greatest thing ever.
- You love our bread, and our chocolate is like crack to you. You'd think that you'd moved to France or something...
- Butter on bread will fuck you up. You use Mayo all the time, but we use butter/spread, and it messes with your minds.
- You quickly learn that Europe is a continent, and that cultures across the continent are very different to one another. You also learn that no one knows US history that well, or that we had a war with you (since we have basically had a war with everyone at some point).
- The drinking culture is a really interesting one. Some love it, some hate it. It's a staple of British life
- We get paid a lot less than you do, but your money will go much further because you're not spending it on healthcare. You'll also get taxed a lot, but ultimately you'll earn enough to be comfortable, and a comfortable life in the UK is nice.
To answer your question, you're more than welcome here, and it's much easier to get a visa to the UK for you than for us to go to the US. Expect some people to give you shit for Trump, but give them shit back for Brexit and electing the Tories for 15 years.