DST

Criticism of DST
DST is not universally accepted and many localities do not observe it. Opponents claim that there is not enough benefit to justify the need to adjust clocks twice every year. The disruption in sleep patterns associated with setting clocks either forward or backward correlates with a spike in the number of severe auto accidents, as well as lost productivity as sleep-disrupted workers adjust to the schedule change. It is also noted that much effort is spent reminding everyone twice a year of the change, and thousands are inconvenienced by showing up at the wrong time when they forget. Since DST exchanges morning daylight for evening daylight, late sunrises occur when DST is in effect either too far before the vernal equinox or too far after the autumnal equinox and darkness in the morning can be undesirable for early risers like schoolchildren and workers who begin their workday at 8:00 A.M. or earlier.
There is also a question whether the decrease in lighting costs justifies the increase in summertime air conditioning costs. While many people use more sunlight under DST, most people also experience more heat, which prompts many people to turn on the air conditioner during the warmer afternoon hours. When air conditioning was not widely available, the change did save energy; however, air conditioning is much more widespread now than it was several decades ago. Air conditioning often uses more energy than artificial lighting. It was for this reason that Arizona rejected DST and opted to stay on standard time all year [citation needed].
It is also speculated that one of the benefits—more afternoon sun—would also actually increase energy consumption as people get into their cars to enjoy more time for shopping and the like.
No formal studies have been performed, but an enormous amount of time has been spent by software developers to deal with the fact that 2400 hours past 2pm is not necessarily 2pm 100 days later.
For example, during a North American time change, a fall night where clocks are reset from 3 AM summer to 2 AM winter time, times between 2AM and 3AM will occur twice, causing confusion in transport schedules, payment systems, etc. On a more trivial note, this also means that people born during one of those two hours have no way to know which one it really was unless someone like their parents bothers to make an according note in their baby photo album since birth certificates normally don't pay attention to this aspect. Aside from astrologists this doesn't actually cause harm to anybody, but it's a bother to people who would like to know their (almost) exact time of birth and have the bad luck to be born on such dates.
Some studies do show that changing the clock increases the traffic accident rate.[1] Following the spring shift to daylight saving time (when one hour of sleep is lost) there is a measurable increase in the number of traffic accidents that result in fatalities.
Some campaigners in Britain would like the country to stay on British Summer Time (BST) all year round, or in other words, adopt Central European Time and abolish BST. Alternatively, some would like Britain to adopt Central European Time and jump forward another hour during the summer (adopting a Single/Double Summer Time from Britain's perspective). This would make winter evenings longer, thereby reducing traffic accidents and cases of seasonal affective disorder. Opponents point to the longer hours of darkness on winter mornings, especially in Scotland, the north of England and Northern Ireland which might well cause an increase in road accidents. In response to this, there have been proposals to introduce legislation to put Scotland on a different time-zone to England & Wales. [1]
DST is particularly unpopular among people working in agriculture because the animals do not observe it, and thus the people are placed out of synchronization with the rest of the community, including school times, broadcast schedules, and the like.
Other critics suggest that DST is, at its heart, government paternalism and that people rise in the morning as a matter of choice because many people enjoy nighttime hours and their jobs do not require them to make the most of daylight. Different people start their day at different times (office workers start their day later than factory workers, who start their day later than farm workers), regardless of daylight saving time.