Too many MBAs are sent into the world with bravado and enthusiasm and confidence.
The problem is that they also lack guts.
Guts is the willingness to lose. To be proven wrong, or to fail.
No one taught them guts in school. So much money at stake, so much focus on the numbers and on moving up the ladder, it never occurs to anyone to talk about the value of failure, of smart risk, of taking a leap when there are no guarantees.
It's easy to be confident when you have everything aligned, when the moment is perfect. It's also not particularly useful.