Not being British
Before coming to London for the first time, most people have this idea in their heads that everyone wears tweed, has spent significant time in a countryside cottage, and has a British accent. As soon as you get on the tube for the first time and realize you don't even recognize what language the majority of people are speaking, you realize that this isn't the case.
Londoners really fancy not being British. They are French, Afgani, Canadian, Australian. Expats from America, au pairs from Germany, tourists from Japan, students from Pakistan. I am actually surprised when I hear someone with a British accent. Likewise, because so many people here are actually English Language Learners, Londoners are usually shocked when I tell them my accent is not British, but Texan (y'all!).
Most Brits, it seems, don't even live in the actual city of London, but in the 'burbs or villages on the outskirts of the big city.
Weirdly, this was something very disappointing to me at first, but now I love how big of a melting pot London actually is!