I am from the UK, and my favourite aspect of British English is the thousands (literally thousands) of ways we have to say things. I'll be posting very British sayings here regularly so you can recognise them when you hear them and use them in your own speech (conversation not formal!).
Very British saying 1: 'the bee's knees'
If you refer to something as 'the bee's knees', it is of excellent or very high quality.
'Do you like my new car? I think it's the bee's knees!'
'You should try this new coffee. It's the bee's knees'
You can also use 'the bee's knees' to talk about people:
'Thanks for making me a cup of coffee. You're the bee's knees!' (you are being affectionate)
'I don't like him at all. He thinks he's the bee's knees' (when you're talking about someone you think is arrogant).
Good luck with 'the bee's knees'!