Negativity, thinking that everything will go wrong, that it can’t work, not having faith in self intuition. All of this is not useful to a living being who has to explore the world and find the advantages to win the fight for survival. Or more simply, to feel good and be happy.
But it seems that negative ideas “take” the human being more than positive ones. A scientific psychological study confirms this. The solution then is to surround yourself with positive people. Get infected by their trust and return some of it to them. At least if you want to achieve a technical objective, which requires effort and long periods of work, the belief that everything will work and go well is not something that can fail.