One thing1 that visitors to this country probably find odd is the British obsession with queueing (or standing in line for any North American readers). Of course, people in other countries form queues or lines for things, but I don't think I've ever visited anywhere else where it has become such a pervasive part of social behaviour.
I was thinking about this this morning, while waiting for the bus. The obvious, orderly queues are fairly easy to get to grips with: join the end, and don't under any circumstances attempt to push in ahead of anyone else — doing so will only result in holes being burned in the back of your skull by the people behind you, and a chorus of 'tutting' and sub-vocal muttering about your lack of manners. No, the tricky blighters for the novice queuer are the crypto-queues. Crypto-queues can form anywhere that the queue is not physically constrained into a straight line, but seem to be particularly common at certain bus stops in Oxford where people approach the stop from either side. The vital thing to remember is that just because there doesn't appear to be a line, it doesn't mean that there isn't a queue. Everyone in the loose cloud of people waiting knows exactly the order of arrival of all of the other members of the cloud.
When the bus arrives, this order is adhered to by subtle use of body language. If you happen to be nearer to the bus, but someone further away arrived at the stop before you, you signal permission for that person to board ahead of you by stepping back slightly and inclining your head towards them. Each person performs this ritual towards the person before them in the crypto-queue, and the cloud unreels itself rather gracefully into an ordered embarkation. You occasionally get people who don't spot the signals, and they get holes burned into the back of their skulls in the time-honoured tradition. Elderly ladies are particularly proficient at this form of social enforcement.
1 Perhaps that should be "one of the many things" :-)