That you should never throw out your shopping receipts because they've all got lottery numbers printed on them (the rationale being as far as I understand it that: shoppers will always ask for an official receipt, and the shop will thereby not be inclined to not record the sale for tax purposes). Why don't we do that?
You can fit one fully grown adult and at least three children onto a scooter.
Even large dogs fit quite nicely in the space underneath a scooter's handlebars, and can be trained not to jump out while their owner is doing sixty in the middle of heavy traffic.
That road rage is a concept largely confined, I think, to the British Isles; despite the density of traffic here, no one - I repeat, no one - gets upset.
That the one true universal language is spontaneous mime.
That drunken fighting in the streets is a cultural phenomenon, unrelated to the availability of alcohol well into the early hours (I've seen one drunk person in my whole time here).
That television programming back home looks an awful lot better once you see what's described as 'entertainment' outside of the UK.