The decor varies greatly in the offices of the 550 CEOs, government officials, and heads of NGOs interviewed as part of our research on leadership — but hands down, photos are the most popular accessory. There are some shots of families and vacations, but most of the pictures show these senior leaders with prominent people. Playing golf with Jack Nicklaus. Smiling with President Obama at a state dinner. Laughing with another CEO at Davos.