(FORTUNE Magazine) – "You have a problem and you will fix it, or I will replace you. Hell will freeze over before this CEO implements another employee benefit in this culture.... You have two weeks. Tick, tock."

This little diatribe is from Neal Patterson, CEO of Cerner, the No. 56 firm on FORTUNE's list of the 100 Best Companies to Work For. (Our bad.) In an e-mail to his Kansas City managers last month, Patterson's remedies for the office's sloth included: weekend meetings, time clocks, and a 5% staff reduction. Offended employees at the health-care IT company returned fire, posting the invective on the Web and driving Cerner's stock down 20%. Although Patterson followed up with an apology e-mailed to his entire staff, he maintains that he was just trying to motivate his workers. "I did it with a lot of satire, never thinking it would be communicated to my associates or broadcast to the outside," he explains. "But I lit the match. That match has started a firestorm."

--Alynda Wheat