Especially as a product manager, sales or marketing manager, this thinking error can happen very quickly.
It is not uncommon for me to agree to a project despite a bad gut feeling and less than ideal conditions. In many cases, the gut feeling is not wrong and the project becomes difficult, many unforeseeable problems arise, misunderstandings exist and thus everyone involved is rather stressed and has a bad experience. During the debriefings, it then happens quite often that I find myself making statements like "it was still good that we did the project because we were able to learn a lot". The original goal was actually that we could implement a successful, educational and sustainable project for the client and for us. Since this result did not materialize, I can now either:
a) try to make the project a success after all
b) admit to myself that it was a mistake to start the project under these circumstances or
c) by adjusting the objectives and a bit of self-deception, still call the project a "success", in that it is enough that we have learned something from it.
Of course, failures and difficult projects are also very important for us, but one should also be able to admit this 100% in order to learn effectively from it.
In my view, it is a great competence when someone can fully admit to mistakes and dedicate him or herself to the learning process in order to avoid the mistake in the future. It should not hurt to make a mistake, but should evoke a good feeling of "Yeah, now I've learned something again!". For this very reason, it is also important to enable a culture in an organization in which failures and wrong decisions can be openly discussed and learned from.