The work of a leader is different. The skill set that made you a great individual contributor isn't enough. It's not about what you can individually accomplish, but what you can accomplish through others. And that's where the complexity begins. Success as a leader is directly related to your emotional intelligence - your self-awareness, your ability to regulate your emotions, your ability to empathize and connect with your employees. Intelligence doesn't guarantee your success as a leader, but emotional intelligence will.