Check out this video clip of a Keynote by NVIDIA CEO Jensen Huang where he says the following:
"I think one of my great advantages is I have very low expectations... People with very high expectations have very low resilience. And, unfortunately, resilience matters in success. I don't know how to teach it to you except for, I hope suffering happens to you... Greatness is not intelligence, as you know. Greatness comes from character and character is not formed out of smart people, it's formed out of people who have suffered."
It took me many years, a tremendous amount of hard work and lot of setbacks to understand that low expectations and learning to suffer well are two very necessary requirements to build positive character.