I have a feeling that there is a bit more to it than that.

In America it is fairly common for employers tack on a little more vacation time every year for both salary and hourly employees. It isn't too terribly odd to have 1 to 1.5 months off a year after working for someone for 5 to 10 years, but Americans seldom stay at the same job for very long. Either you go off for greener pastures, quit out of frustration, get laid off or simply resign because they fear that prospective employers won't hire you because you stayed at one place for too long.

Deep down, I think we have a serious fear of being considered lazy by our peers.