...realise you're no longer a hip, savvy Londoner!
I arrived in London at 4.45am yesterday and had some trouble topping up my oyster card (bus pass for my non-Londoners), so I decided to just get the bus and pay with cash as it was really early and the bus stop was deserted. Imagine my surprise when I was informed that "cash is no longer valid tender on TFL buses." So flustered was I, that I launched into French with the driver who looked at me weirdly and motioned for me to get on, for free. Apparently they changed the system about 5 months ago...thank God for kind drivers sha.