We should take a moment to pay tribute to the Tube, an imperfect and frequently frustrating public transit system, but one which nonetheless has a certain style to it.
The tube map itself is a thing of beauty - 45 and 90 degree angles only. Frequently departs from the reality of the geography of London, but nonetheless the Tube Geography is somehow almost more real. I don't know about native Londoners, but I tended to think in Tube Space while I was there. The map, aside from minor service changes and expansions, hasn't changed all that much since the original 1931 design.
Cities which primarily rest on their public transit system - New York, London, Paris - are fundamentally different from all other locations. A place can't be "that kind" of city without a massive well-functioning subway system, combined with other modes of transport.
The Tube is hot in the summer (no AC), has frequent service disruptions, and never seems to manage to meet its maintenance timetables. But, warts and all, the Tube is a fundamental part of the fabric and personality of London itself.
Mind the gap.