Having lived for a brief period abroad, the UK isn't that bad in my opinion. But I have a few thoughts.
1. High streets. Everywhere in the country, they all look the same, with the same shops, and very few cities have their own distinct shops, which I think contributes to a general theme of cities not having their own distinct culture, except perhaps London, Birmingham, Manchester, Cardiff and Edinburgh/Glasgow.
2. Public transport. Dreadfully run, infrequent and awfully expensive.
3. Religion. The sooner we become a secular country the better. And publicly-funded religious schools should not exist.
I'm sure there are many more but in actual fact I think anyone who lives here is incredibly fortunate.