I think I am only slightly in a different position than lots of folks.
I have been the the UK more than most folks I know and my brother lives there, so I get to hear his input.
My move to London is set for the second week in Aug., so its coming right up. After talking with my brother, there are a few things that I am aware I will miss:
1) Weather. I live in California. I have twice the number of shorts that I do long pants.
2) Recreational Shooting. I enjoy target and skeet shooting and won't be doing any of that in the UK.
3) Mondo Stores. This is a double edged one. The convenience of walking into a home depot, Barnes and Noble, etc. is nice. By the same token, the smaller mom and pop shops are often a great pleasure.
4) Driving on the right.
5) Nearly year round BBQs.
6) Wide warm beaches.
7) Being less than a two hour drive from snow, beach, mountains, desert, lakes, forest.
Gas prices
Thats all I can come up with for now. I am sure that once I am there and really settled, there will be more subtle things that I discover I miss.
R