I find this a fascinating topic! We had a lovely Ukrainian family living with us for a year and it was only from living so closely with people from a different culture that made me really examine our own. Though culture is obviously the things that have been listed already - art, music, landscape, religion, traditions, the monarchy etc - there are so many things that I noticed as ‘British’ that I’d never put any thought into before.
We are excellent timekeepers and get worked up into a state of near panic if we think we may arrive even a minute late. Other cultures are much more relaxed over timekeeping.
We are obsessed with food hygiene and won’t eat anything that had been left out of a fridge for a couple of hours. Our guests would cook chicken from frozen, and eat from a pan of food that had been left on the hob for days. They never got sick. It made me question why we’re so hung up out it.
We would rather cut off a limb than ask someone for a favour. Because of this, we implicitly understand that if someone asks us for a favour it must mean that the world will literally stop spinning if we refuse and so we feel an enormous obligation to agree, even when we really don’t want to. Other cultures are happy to ask for things that we would consider to be the epitome of cheeky fuckery, but they’re also very happy to say “No, I don’t want to” and there are no hard feelings. As a British person, that blows my mind!
I also think a lot of our culture is regional. I’m 50 and I’ve never been privy to morris dancers, maypoles, brass bands or cricket in my lifetime. In my area, people are generally very friendly and will always help others if they can. I love this and feel prouder of my regional identity than my national identity.