While they aren't as public about it as CBS anchor Katie Couric was in a recent magazine article, it's natural to have second thoughts in the first month or two of any new job, said John Challenger, chief executive officer of Challenger, Gray & Christmas, based in Chicago.

Depending on the severity of the regret, Challenger suggested meeting with a supervisor to discuss the situation or leaving before the regret begins affecting job performance, Challenger told the Chicago Sun-Times.

The four reasons people leave a new job are: the position is different from what the job seeker perceived,

the new employee does not get along with his or her supervisor, the new employee does not mesh well with co-workers, and the employee is not getting the results expected.