I can’t believe I’m defending optimism because I’m thr least optimistic person in the world.

I'm defending realism even if I'm extremely pessimistic, so... welcome to the club.

So if a pilot is in a failing aeroplane [...]

From the pilot's PoV, both optimism and pessimism mean the potential loss of the tiny chance of survival - one because it underestimates the effort necessary to achieve the desired result, another for giving it up. While realism is the option that actually allows you to seize that chance, and say "we're probably fucked, but I can increase my odds of survival with my effort".

From the passengers' PoV: if they know that the plane will crash, and can't realistically do anything about it, optimism means wasting their likely last moments of life. While realism means accepting "I'm going to die in a few moments; better grab the gorgonzola from my bag and enjoy it, I probably won't be able to gift it to my cousin. Komm, Susser Tot!"

And this brings me back to optimism. How many times have you watched a sports game

I don't watch sports, but I think that what I said still applies: optimism leading to less effort than the necessary to win, pessimism leading to giving up, realism leads to a cold analysis of the situation and what should be done to get the best result.