Years ago I lived in Morningside, our local celebrity was JK Rowling as it was at peak Harry Potter time. I was in Safeway (which is now a Waitrose I believe) and JK was in the queue in front of me. Brilliant conversation followed with overly helpful / officious checkout bloke
Bloke: This chicken is on buy one get one free, would you like another one
JK: Its okay, I only want one chicken
Bloke: Yep, but the second one is free, I’ll get one for you
JK, Really, its fine, I’m in a rush and would just like to pay
Bloke: You can’t turn down a free chicken
JK: Really, I’d like to pay, now.
Bloke: (now becoming quite forceful and loud) Mrs Rowling, I know who you are and I know you can well afford lots of chickens but you mustn’t pass up offer like this!
JK: enough now, take my money.
She didn’t flounce but it was close