The fact that you can't buy anything medically meaningful without prescription at a pharmacy. But at the same time, as the previous poster said, why would you need to, since paracetamol cures anything. The amount of plastic spoons and syringes from in my friends' drawers from all the bottles of Calpol they went through when their children were little is terrifying.
I was amazed that some just routinely give paracetamol syrup to their babies/toddlers so they sleep better, kind of just in case. 
None of them seemed to care to do any research on the long term side effects...(maybe it's just my DH's friends).
My DH owned a washing up bowl which I hated because it was in the way and got rid of promptly, but he hotly disputed that ANY British people don't rinse and that it was all my imagination. Until we went camping with his friends and when our bowl ended up in his friends tent in the end, the friend walked in saying he washed it for us, he walked in carrying what looked like a small cloud of foam, and passed it to me. Inside the cloud was the bowl. 
To be fair I think it's dying out.
Next is not a quirk, but my DD introduced all her friends to cheese slicers (mentioned previously) and also nose unblocking sprays, their minds were blown 😁
Obviously either is widely available, so you'd think everyone knows about them, but to her friends (East Midlands) both items were a complete revelation.
They slept through their childhoods breathing through the mouth when their noses were blocked...And now they could cut really thin slices of cheese effortlessly :)