From a London perspective
It's nice to have seasons, although prefer the colder ones to be a bit shorter and a tad warmer. Because hot weather in summer is not guaranteed, people tend to be in extra good moods on sunny days and it's lovely.
Outdoor screenings in unusual locations - often become pop up ice rinks in winter
Bright winter mornings
When winter starts to end and you see daffodils and know spring is on its way
Building snowmen with kids when we get snow
Cherry blossom
Beautiful architecture
Long summer evenings and BBQs
Free health service
Lots of museums, galleries, theatres, comedy
Choice of activities - no matter how random the activity, they'll be somewhere to do it
Corruption exists of course and our government seems deep in it, but on a daily level you don't need to bribe people etc. You can just get on with your job/business, pay tax and be left to it
Multicultural - a real melting pot and a variety of food to match
Tower Bridge - reminds me of a fairytale
Generally accepting and tolerant, but there is more of a racist undercurrent in recent years unfortunately, which seems exacerbated by Brexit here, but I don't think this is limited to UK
Fish and chips on the beach
People don't tend to care what sexual orientation you are or what you identify as
Buzz in town on a Friday evening before a bank holiday Monday
As it's small, it's fairly easy and quick to get to most places - beach, countryside etc
Lots of good music and venues
Beautiful parks and woods
Humour and banter
Lovely market towns
Predictability of certain areas - seasides have promenades, fish and chips, an elderly couple on a bench watching the sea, tourist tat; generic high streets will have a chicken shop, a nail bar and a charity shop
Christmas - lights, Christmas fayres,
I don't go clubbing anymore, but there are some great clubs
Drinks by the river
I love Edinburgh, especially during the festival
Holkham beach, Norfolk
Where do you live now? What part of the UK are you going back to?
Now for the bad bit, so scroll on if don't want to know!
The worst thing about UK at the moment is we seem on a bit of a self-destruct mission and it's hard to see it happening. Brexit and covid are very divisive. It's expensive and poverty has risen.