Moderating optimism is overrated. Most people should make an effort to be more optimistic, due to our biological negativity bias. That will serve them better.
It would be in line with the fact that you've noticed people who got in trouble for being overly optimistic ("too optimistic for their own good")
On the other hand, you may also think that is serves little purpose in a civilized society (by which I mean a society where making a mistake/a judgment error is not punished by death by your environment) and may be a hindrance in your life.
I don't have an opinion about it in general but I do think humanity is being overly optimistic about its ability to stop/tame climate change while aiming at achieving/conserving a way of life that relies on energetic abundance. It looks very much like collective denial to me. It's like hearing a addict telling he can stop tomorrow if he really wants. Let's hope I am wrong because if I am right it's not gonna be pretty, it's already not looking great.