Elon Musk used to rewrite the code of engineers working at Zip2, a company he co-founded with his brother in 1995, even after they had gone home.
Musk was known for his demanding management style and worked tirelessly, often for long hours, without breaks. He expected the same dedication from his team.
Musk, according to his biography by Walter Isaacson, didn't initially want to be a CEO but realized that to have the authority to build products, he needed to hold the CEO position.