Huge point brought up here: the essay can be about really anything as long as it's incredibly sincere and you understand and mean everything you're writing about. The bit about the essay being "funny, insightful, and wickedly intelligent" should come from your own personality if you're writing about something you truly know.
The most interesting ideas are the ones you never put into words because they seem to weird or too obvious.
Giving yourself some distance from the essay helps you to see it the way a first-time reader would see it.
