Wonderful advice from @intparent We too focused on what the kid wanted to share about himself, and then figured out which prompt it might credibly fall under. My kid was applying only to LACs and, as an upper middle class white kid with few significant challenges in his life (unless you count being reluctant to sit down and read), we worked backwards from what mattered about who he is. So, he didn’t start out with “I want to write about x” – he started out thinking about what why would the school want HIM instead of some other upper middle class white boy – not in terms of ECs but in terms of character and values. Then he figured out how to illustrate those qualities in an amusing way.
As always, key advice in essay writing is “show, don’t tell.” For ex., illustrate how you are open-minded through anecdotes, rather than say “Being open-minded is an important part of me.”