2 Try explaining that when you get to work late. The average U.S. city commuter loses 38 hours a year to traffic delays.

3 Wonder why you have to set your clock ahead in March? Daylight Saving Time began as a joke by Benjamin Franklin, who proposed waking people earlier on bright summer mornings so they might work more during the day and thus save candles. It was introduced in the U.K. in 1917 and then spread around the world.

4 Green days. The Department of Energy estimates that electricity demand drops by 0.5 percent during Daylight Saving Time, saving the equivalent of nearly 3 million barrels of oil.

5 By observing how quickly bank tellers made change, pedestrians walked, and postal clerks spoke, psychologists determined that the three fastest-paced U.S. cities are Boston, Buffalo, and New York.

6 The three slowest? Shreveport, Sacramento, and L.A.

7 One second used to be defined as 1/86,400 the length of a day. However, Earth’s rotation isn’t perfectly reliable. Tidal friction from the sun and moon slows our planet and increases the length of a day by 3 milli­seconds per century.

8 This means that in the time of the dinosaurs, the day was just 23 hours long.

9 Weather also changes the day. During El Niño events, strong winds can slow Earth’s rotation by a fraction of a milli­second every 24 hours.

10 Modern technology can do better. In 1972 a network of atomic clocks in more than 50 countries was made the final authority on time, so accurate that it takes 31.7 million years to lose about one second.