Yes.
I read a paper* years and years ago that concluded that optimists, whilst as a rule happier than pessimists (obviously), are much less accurate in their predictions when you test the two groups’ abilities to estimate outcomes in a controlled way. So being an optimist is good because you’re innately cheery, something that has quite a few benefits, but this is in spite of, rather than because of how things actually turn out. Generally speaking, optimists are happy and wrong, pessimists are miserable but right.
It was a revelatory moment for me, explaining as it did why a) I am always right and b) why everyone else is so **** stupid all the time. 😉
*(I can’t find the paper, annoyingly enough, so can’t check how valid a bit of research it was.)