Many of us have a very unrealistic picture of what a good leader looks like: Slow to criticize, generous with praise, doesn't shout, seeks harmony and prefers agreement over disagreement.

This type of leader certainly exists, but after 10 years of researching and interviewing some of the world's most successful people — from founders and executives to athletes and entertainers — I've found that the majority have one thing in common: a willingness to put up with clashes of interest in their company for the sake of change and progress.

Take Microsoft co-founder Bill Gates: In addition to his groundbreaking innovations, the billionaire is best-known today as a kind, compassionate and soft-spoken philanthropist. But decades ago, a much younger Gates earned a reputation as the office bully.

According to James Wallace and Jim Erickson, authors of the 1993 Gates biography "Hard Drive: Bill Gates and the Making of the Microsoft Empire," Gates was notorious for sending "critical and sarcastic" emails — often referred to as "flame mail" — to his employees in the middle of the night.

More than one "unlucky programmer received an email at 2:00 a.m. that began, 'This is the stupidest piece of code ever written,'" the book recalls. Former Microsoft employees described the office as a very confrontational environment, with Gates being "demanding" and the work "intense."

Another anecdote comes from Joel Spolsky, founder of Stack Exchange and a former program manager assigned to Microsoft's Excel product line. In a 2006 blog post, Spolsky writes about his first in-person product spec review with Gates. In addition to several other managers, there was also a person "whose whole job during the meeting was to keep an accurate count of how many times Bill said the F word."

"The lower the f***-count, the better," Spolsky recalls. As the meeting progressed, the questions Gates directed at him "got harder and more detailed."