Developers have been messing up time and calendars over the years, and it still seems to be happening. Why are times and timezones still so confusing for them?

The reason: it is an insanely complex subject. The fact that countries change the clocks at different times of the year and change the time zone classification on a whim, it is not only frustrating for those in the timezone but to all developers out. Watch the video for the explanation:[Computerphile]