The idea is American in origin, invented by Benjamin Franklin to save lamp oil and aid the economy. The reason the change is at 2 A.M. is because most people are asleep, bars are already closing, and few trains operate.
Daylight Saving Time is an international thing and very political. This map page has information about countries which use DST. Some countries adopt it to be Western while others drop it to be independent like Kazakhstan breaking away from Russia or the Palestinian Territories changing the dates to be different from Israel.
Allowing more daylight is desirable for much of the world away from the equator. Web Exhibits continues their great DST explanation with a neat interactive map showing daylight versus nighttime.