Gates built Microsoft into the world's biggest software company, but the success came at a cost to employees who endured his meltdowns and browbeating. Gates' Microsoft cofounder, Paul Allen, once described working for him as "being in hell." Gates' successor, Steve Ballmer, was also known to have an explosive temper. The culture established by leadership trickled down throughout the org chart, to the point where Microsoft's different units were once depicted in a cartoon as warring gangs.