We let ourselves be gamed every day by one of the oldest technologies of all: the calendar. Because it displays our nonscheduled time as empty space, our calendar apps encourage us to pack our days with events. Think how differently we'd interact with our calendars if the default wasn't for timeslots not to be empty – if, instead they were prepopulated with tasks like thinking, writing, and planning. We’d be far less likely to neglect the opportunity costs: Every time we accept an obligation, it would be clear that we are giving something up.
Another calendar problem is related to what behavioral economist Gail Zauberman and John Lynch call “resource slack.” Their research shows that when people estimate future time and money we are overly optimistic about how much flexibility (slack) we’ll have. But we’re even more unrealistic about time than money. Lynch, who was my dissertation advisor used to give me this advice: When someone asks you to do something in a year, ask yourself whether you’d accept if it were happening in the next two weeks. Based on our calendar, it looks as if we have nothing to do year from now. In reality, though, our typical week next year will look a lot like this week. But until on my calendar starts to simulate that, I'll keep surrendering my days to stuff I never should have scheduled.
Dan Ariely writing in Wired Magazine