What are some of your favourite tropes/recurring bits?

What are some of your favourite tropes/recurring bits that no matter how many times you find in a fic you still love?

I personally love when their friends bet money on them for various things, and how Luna often gets given cryptic, seer type one liners that come true. Let's not forget the endless supply of chaise longue for them to have sex on, makes me laugh every time (if you haven't noticed this yet, now you won't be able to unsee it!)

There are so many, give me yours!