Let's start with the transport system.
Followed by all those really important people in suits walking down pavements talking loudly into their phones about Directorships.
But tbh, mainly the transport system. You seem to have a maximum speed limit of 5mph, no matter what form of transport. I can walk faster than that. And had to. Because your buses are shit and break down in the middle of Caledonian Road, thus producing gridlock IN SECONDS! That's sort of impressive in its own sweet way.
London smells. I'm not even being childish. It's a fact London stinks. And when you live there (I speak from twenty years experience) you get so used to the putrid air you don't even notice it.
Too many cops as well.
You're welcome to it.