Time zones can be stupidly-frustratingly-annoyingly stupid, frustrating and annoying if the person you want to talk to is never online because it's midnight.
I live in New Zealand which causes a problem if I want to talk to most people on the 'Isle and so I propose that time zones be abolished so that we can all live in the same time. (This is not a grammatical error by the way.)
Making everyone be on the same time would be rather useful... it would cause less confusions and worry about, "Oh, what's that in my time?" but you couldn't have everyone on the same daytime schedule. As BlueJay says, Americans will sleep when it's dark there, which will be when British folk like myself are awake, etc.
Time zones are inconvienent, but practical in the day time here night time there sort of matter. Daylight Savings is stupid in this day and age when most of us aren't farmers anymore (or is that just us conglomorate loving Americans?). I also hate leap years. They drive me crazy. Why don't we just rearrange the months and make them evenly spaced, and account for those extra hours or whatever in the regular years?