Yukari Iwatani Kane on Apple under Tim Cook:

Apple under Jobs was a roller coaster, but Cook’s operations fief was orderly and disciplined. Cook knew every detail in every step of the operations processes. Weekly operations meetings could last five to six hours as he ground through every single item. His subordinates soon learned to plan for meetings with him as if they were cramming for an exam. Even a small miss of a couple of hundred units was examined closely. “Your numbers,” one planner recalled him saying flatly, “make me want to jump out that window over there.”

Cook had made a particular point of tackling Apple’s monstrous inventory, which he considered fundamentally evil. He called himself the “Attila the Hun of inventory.”

Meetings with Cook could be terrifying. He exuded a Zenlike calm and didn’t waste words. “Talk about your numbers. Put your spreadsheet up,” he’d say as he nursed a Mountain Dew. (Some staffers wondered why he wasn’t bouncing off the walls from the caffeine.) When Cook turned the spotlight on someone, he hammered them with questions until he was satisfied. “Why is that?” “What do you mean?” “I don’t understand. Why are you not making it clear?” He was known to ask the same exact question 10 times in a row.

No one questions that Tim Cook’s leadership is vastly different from that of Steve Jobs. But that doesn’t necessarily mean he’s any easier to work for. This paints him as demanding, but in different ways.

Dolly Singh (the former Head of Talent Acquisition at SpaceX) on Elon Musk rallying the troops after a problematic launch:

I think most of us would have followed him into the gates of hell carrying suntan oil after that.  It was the most impressive display of leadership that I have ever witnessed.  Within moments the energy of the building went from despair and defeat to a massive buzz of determination as people began to focus on moving forward instead of looking back. This shift happened collectively, across all 300+ people in a matter of not more than 5 seconds. I wish I had video footage as I would love to analyze the shifts in body language that occurred over those 5 seconds. It was an unbelievably powerful experience. 

Musk gets a lot of credit for being a visionary (and rightfully so, of course), but his leadership in getting incredible people to do incredible things may end up being just as important a trait.