This bidimensional model is weird.

• I can imagine pure mania: assigning a 100% probability to everything going right
• I can imagine pure depression: assign a 100% probability to everything going wrong
• I can imagine pure anxiety: a completely flat probability distribution of things going right or wrong

But I can't imagine pure top left mood. This lead me to think that the mood square is actually a mood triangle, and that there is no top left mood, only a spectrum of moods between anxiety and mania.

I'm with you - I consider myself (and have been called by others) an incredibly optimistic cynic.