As the player of the PC in question, it was definitely a fitting aspect. I suggested the character trait, if not the turning it into an aspect part. I was unsure at the time (as the GM seemed to be) whether it would be appropriate, rules- or feel-wise, to throw a temporary aspect on the PC mid-game, especially if I might start perceiving it as some sort of punishment. There was about a five second period while we discussed it where I felt like we were talking about me getting slapped for, effectively, rolling really well and spending a fate point. But then I realized how easy it would be to get compels and how utterly perfect it was. I would have been fine with it in this instance, but as a house rule or a regular thing I'm not sure. It would have been so much in line with the character, though, that I'm making this specific instance moot by replacing one of my less inspiring aspects with something like Gross Overestimation of My Abilities.
There were no NPCs present that could have placed the aspect on my guy, or this would be a much less opaque topic. Well, no NPCs that weren't A) alligators and B) dead, at least.
One other problem that I perceived arose from a large percentage of the game taking place just between PCs. Is it possible/acceptable/desirable for PCs to compel other PCs or place aspects on other PCs? In the cases of a compel, would the consequences that arise from pursuing the negative side of an aspect be severe enough to warrant a fate point? It didn't really seem to me like that would work very well. If my smartass, in other words, pissed off Bear's buttkicker, could that be considered a compel on an I'm Smart, But My Mouth's Smarter aspect? Or would it only work if the consequences were going to be especially bad? Like if he was definitely going to kick the crap out of me? Anybody else's experience on this?
That might be a bit off-topic, and I'll start a new thread if deemed necessary (but later, because I've got to head off to work).