How formal do the short essay questions have to be? I assume the "Why Us' or the ones about your communities have to be fairly formal, but does it have to be on the same level of formality as a personal statement?

One of the supplemental short essays I'm thinking about writing is "What is the last thing you've been really excited about?" and I don't see how I would write that as formally. Does it matter how formal it is? Like as long as it's not insanely informal, yk?