@darius I once had to work on a time zone problem. I remember explaining to the boss that time zones are just madness because they define more than a simple GMT offset; they also set your DST dates. And that matters in Arizona, where you're on Mountain time but don't observe DST, except for the Navajo nation, which does. He asked why that was so important, and I noted that tribal lands are over 1/4 the land mass of Arizona. Then he knew my pain.
@roadriverrail I like to point out the 15, 30, and 45 minute offset time zones. Also the fact that any of these rules can change whenever some government body somewhere in the world decides to change them for some reason.