Most amount of bookstores per square km anywhere on Earth along Charing Cross Road. Bookstores everywhere!
Camden market, Borough Market, Greenwich Market and other markets where people who make or grow stuff can sell it right to the consumers
WHSmith, Marks and Spencers and Woolworth's still exist! (They left Canada about 15 years ago, but we had them when I was a kid)
That Mitchell and Webb Look, QI, Dr. Who and Time Team on TV
People don't think electronic dance music is only for gay people
Crispy Duck restaurant in Chinatown
If you have a Canadian accent no one can peg where you come from, countrywise or social class wise
Guys aren't still wearing those stupid baggy rapper pants that went out of style in the late 90s that people trying to be gangsta still wear in North America
You can read EM Forster and see the places he wrote about in 1908 in existence now!
Homeless people don't freeze to death every winter and exhibit missing body parts due to frostbite :( something I used to see all the time in Byward market in Ottawa
Buildings that are twice as old as the country I come from!
Architecture that does not prominently feature gray concrete as its main building material
Lots and lots of museums! If anything remotely historical ever happened on that location- like the invention of the q tip or something, there will be a blue plaque there and a q tip museum with gift shop!