If you are among those who use their cell phone as an alarm clock, you probably do not have great difficulty adjusting to Daylight Saving Time coming and going twice a year. If you fall into that group, you probably also have a computer or tablet that adjusts time automatically. Our cable TV boxes adjust automatically also. So what's the big deal?
In September 1999, Israel made an unscheduled early change from Daylight Saving Time (DST) to standard time to accommodate a religious week of prayers. The Palestinians refused to live in a “Zionist time zone” so they stayed on DST. Three terrorists secretly received a bomb from the West Bank and tried to drive it to an Israeli bus station but the bomb exploded before they got to the bus station. Its timer had been set in DST but the three did not realize they were an hour behind schedule because of the standard time in Israel. They were obviously having trouble with DST.
When DST happens in the spring, time moves forward an hour at 2 AM on Sunday morning. This is the only hour during any year in which no babies are born and no one dies. There is no history made. No aircraft take off, no crime is committed, and in other words, nothing happens. That hour just does not exist.
And then, when DST happens in the fall, time moves back an hour at 2 AM on Sunday morning and the time between 1 AM and 2 AM is repeated. Consider a twin baby born on the Sunday morning at 1:05 AM and then its twin born an hour later at 2:03 AM; the one born an hour later would technically be older since the official time of birth would be 1:03 AM. Confused?
DST was originally enacted as a way to conserve energy during World War I but recent studies have shown that actually energy saved is minimal. But, we do almost universally enjoy the shift in work time so we can do more in the evenings after work.
For those who have trouble with DST or who just want stability in time, maybe consider China. Its geography would cover at least 5 normal time zones. But, China has just one time zone for the entire country and it does not observe DST. So while sunrise in late March in Beijing is 6 AM, the sun rises in Kashgar in the far western area of China at 9 AM. And then, simply go a few miles west from there to Tajikistan and time immediately changes 3 hours. So, even though quite time-stable, there may be just a little confusion on leaving the country.
Daylight Saving Time is common throughout the United States and Europe but it is not common in South America or Africa.