It's the American mantra. "How are you? I'm busy." Many people believe that if they do not profess to be busy they are perceived as slackers. That is cultural pressure. The Japanese have had to ease up on that pressure in recent years as well after a growing pattern of suicides and heart attacks among middle-aged men who were simply done and couldn't give any more.
A counter stream is now weaving itself into this workaholic culture of the American dreamer who must work hard to achieve a better lot in life than his or her parents. Many younger people want more family time, whether in the form of paternity leave, longer maternity leave than the standard skimpy six weeks, half days on Fridays, working four longer days earning them a three-day week-end, more vacation time than the "standard two weeks" (so you forego your family vacation because you had a sick child???), working from home, and a clearly defined work schedule that doesn't stretch into the wee hours or includes responding to work emails and texts 24/7.
Makes sense, it's a quality of life matter. You and I are more than our profession (although it's always good to earn a living doing something you enjoy). Family time, cultural time, friends time, sports and activities time - so many fun things to do besides work. From all I have been reading, more and more employers on this side of the Atlantic get the message and are slowly beginning to inch a bit closer to the European model. Acknowledge and voice your needs.