• They'll dream big and push themselves, you and your team towards bigger achievements than you initially thought possible.
• They have a growth mindset. They crave feedback and new challenges that will push them to grow, they persist in the face of setbacks, they see effort as the path to mastery, they learn from critical feedback, and they're inspired and learn from the success of others.
• They make the code they own or touch simpler, clearer, easier to work with and faster to change. They do this out of habit, opportunistically and continuously.

Source: Traits of Exceptional Engineers