As a climber, you should always try and subvert your optimism bias, in which you will overestimate positive outcomes and underestimate bad outcomes, while at the same time, retain a positive frame of mind. This will often be achieved by being a pessimist on a micro-scale, being paranoid about each placement, each creaky flake, every hold that might snap off; while being optimistic on the macro scale, that you can find a way up this thing, and be safe, that optimism based on a foundation of pessimism.
I suppose this could be viewed as a pessimist held within a bubble of optimism. The opposite of this is a climber who is filled with fear all the time, yet seemingly pays no attention to their gear, or their ability to make it to the next rest, or ability to complete the moves. Such as person jibbers and jabbers, shakes and screams their way up a pitch, all their gear either dubious or falling out as they go, their life (and that of their partners), in the lap of the Gods. Yes, there’s an optimist in him somewhere, but it’s misplaced. The former climber, on reaching a single protection bolt on a death slab will clip their rope in with a locker, or two draws back to back, while the latter, will either just use one draw, or not clip it at all, believing it won’t do them any good anyway (or by completely missing it!).