In an interview, Bill Gates was asked how hard it was for him to learn to delegate. Bill answers with how he had to change his mental model, going from writing code to letting go to optimize for impact.
Yeah, scaling [Microsoft] was a huge challenge. At first I wrote all the code. Then I hired all the people that wrote the code and I looked at the code. Then, eventually, there was code that I didn't look at and people that I didn't hire. And of course the average quality per person is going down, but the ability to have big impact is going up. [...] A large company is imperfect in many ways, and yet it's the way to get out to the entire world. — Bill Gates
You can listen to the entire interview but I've also included the excerpt here:
This idea of "having to let go to optimize for impact" really resonates with me. I've gone through this transition in the Drupal community and at Acquia. I've even written about on a few occasions [1, 2].
— Dries Buytaert