Commonly abbreviated as DST, Daylight Saving Time may refer to any of the following:
1) A plot by the government to screw up everybody's schedule under the guise of energy savings, because they can.
2) A mild method of population control -- DST changes correlate well with increased vehicular and cardiac related fatalities.
3) Another reason to punch your S.O.
in the mouth, since at least one of the clocks in the house will not get updated, and that will invariably be the clock you consult before going to work, sleep, or to watch your favorite live sporting event.
Late co-worker: 10AM?!? Shut the fuck up, my watch says nine.
Some fuckwad: Haven't you ever heard of daylight saving time?
Late co-worker: You ever heard of chin nuts