We're led to believe that intelligence (or sometimes IQ) is purely genetics, but what we fail to realize is that the ceiling is higher than any of us imagined - and we underachieve in respect to our true potential..

That said, we need to be care how we praise people:

Cloninger has trained rats and mice in mazes to have persistence by carefully not rewarding them when they get to the finish. "The key is intermittent reinforcement," says Cloninger. The brain has to learn that frustrating spells can be worked through. "A person who grows up getting too frequent rewards will not have persistence, because they’ll quit when the rewards disappear."

In short, praise people for being smart, and they will likely try to defend that image by taking less risk. Praise people for being hardworking, and they'll work ever harder..