An effective leader develops those around them. Secure leaders give power to others. Good bosses develop their employees.
Successful leaders empower other people.
"The best executive is the one who has sense enough to pick good men to do what he wants done, and self-restraint enough to keep from meddling with them while they do it."
- President Theodore Roosevelt
Empowered people reach their potential.
Just as someone taught you to walk, someone taught you to drive, and someone taught you to read- you have tremendous gratitude for them. They shared what they knew with you and you are better because of it.
When a superior or organizational leader does not empower others, it is oftentimes because of insecurity. Not wanting to share information, contacts, best practices, or give others a chance stems from the fear of becoming obsolete or unnecessary.
That is a lie. Here is a paradigm-shifting thought that I am learning daily: Just as the Way up is Down, Great Leaders Gain Authority by Giving it Away.
Think about it, enlarging others make you larger.