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The ultimate job security, it seems, comes from working for the U.S. government. As one Government Accountability Office (GAO) report found, "it can take six months to a year (and sometimes significantly longer) to dismiss an employee," with an average timeline of 243 days in 2013. And that's if a firing occurs at all: A federal worker's chance of being fired in a given year is just one in 500.

"It ends up being very, very difficult to fire a federal employee even when there is the best of cause," explains Joseph Morris, who served as general counsel for the U.S. Office of Personnel Management in the 1980s. At one point, Morris recalls, he made a list of all the possible steps to fire a federal employee in his era and found it stretch some 30 feet. Today, he says, the list would likely be longer.

These lengthy firing processes can be at work even in cases of egregious misconduct. For example, the Department of Veterans Affairs (VA) expects to take at least 270 days to fire a nurse who operated on a veteran after chugging as many as five beers at a casino.