I personally prefer sunflower_mynah's suggestion of expressive/stoic, as those are actual opposites, where as the others tend to have more room for "well, it depends..." It's possible to be both serious and cheerful, and be playful around certain things but serious around others. Expressive also deals more with a wider range of emotions, so it offers the applicant more room for explanation.

I like the idealistic/realistic one. I know it would definitely be a question I'd have to elaborate on, which is a positive in itself, and I imagine the same would be true for many others.

While I like all of the other fandom related questions as it gives a perspective on how they express their opinions as well as gives the voters something to automatically socialize with them about... I've never liked that one, as it's the easiest to bias votes towards. (i.e. someone who lists a bunch of soldiers could either be pushing towards solider or it may cause them to end up there even if they're more dragoon-y) I think "look up to" could have the same problem in some respects, unless they list how they're different from those characters... and I'm admittedly a bit biased, since I've always loathed answering questions like that. I never know what to say, as there are traits I admire, but looking up to people... to what extent does that imply? I don't idolize people, much less fictional characters, so I always draw a blank there.

... although that's probably just me. DX