Maturity comes with age and experience. I was a believer of it, not anymore. I think it is a mental construct and, more of it is about ourselves.
People come on their reasons which fit their construct. In the end, one has to face themselves and their thoughts. How can we be vulnerable; we have to take high ground for ourselves.
A manager will not tell you why salary is getting delayed or, an investor will not give you any right on the face. An engineer while moving on will not tell you he is leaving for better pay.
We all are vulnerable, and we are all scared of being naked. At the same time, we want to hold high moral ground ourselves and feel rational about the decisions.