Hmm... I disagree that QuietlyInsane is neccessarily better than NoisilyInsane. For one thing, in the state of NoisilyInsane, there's much more likelyhood that people will actually realize that they need to help you out. Mmmn... Proctor Intervention. Yum!
It can also be useful to appear NoisilyInsane, but in a particularly unconvincing manner, so as to trick people into thinking that you are actually SaNe. In this situation, I guess your actual state would be QuietlyInsane, but it might be better expressed as MetaInsane. Or maybe MetaInsane would better be used to describe what happens when you think you're InSane, but really aren't. Or something like (or unlike) that.
You're so crazy that you don't know you're so crazy that you don't know you're insane?
The trouble here is that you are all implying that insanity is necessarily a bad thing.
I don't suffer from insanity. I enjoy every minute of it!