No matter how good you think you are as a leader, my goodness, the people around you will have all kinds of ideas for how you can get better. So for me, the most fundamental thing about leadership is to have the humility to continue to get feedback and to try to get better - because your job is to try to help everybody else get better.
Ultimately, leadership is not about glorious crowning acts. It's about keeping your team focused on a goal and motivated to do their best to achieve it, especially when the stakes are high and the consequences really matter. It is about laying the groundwork for others' success, and then standing back and letting them shine.