I work with people across the U.S. and every time I setup and meeting we have to always clarify the timezone and it's worse when working with Arizona because sometimes they are in Pacific Time and sometimes in Mountain Time since they don't observe Daylight Saving Time.
So, if everyone were on UTC, you could just say "Let's have a meeting at 16:00". 16:00 might be the middle of night for some people or the middle of the morning for others, but who cares? Everyone knows when 16:00 will happen. So, if I agree to the meeting, I don't have to know if they are in Mountain, Eastern, or Japanese time zone, only what time in UTC the meeting is. Done. Easy. No time math.
Who's with me?
International pilots and the army. Just start calling it Zulu time, instead of UTC.
Living in a country that uses the 24h system, you just say "four" or "4 o'clock", the time of day is understood from context 90% of the time. The other 10% you just add "in the morning" or "in the afternoon", or "16 hours".
That would not change at all if you were on UTC.
Most of the scheduling issues are related to the actual time difference between the two geographical places: by the time someone in California is done with breakfast, commute and ready for the meeting, the guys in NYC might be heading out for lunch. But living in a unique timezone won't fix that, the same way it won't fix the Southern hemisphere being always in the 'wrong season'. In fact, it'd aggravate the problem when traveling even a few hundred miles: "uh, what time do banks operate here? Is it too late for lunch?".
The world is a (roughly) spherical body. Sol raises from the East. Learn to think in those terms, and you'll avoid most problems.
10 + 5 = 15
10h - 15 = 19h previous day
Or alternatively, fire up http://www.wolframalpha.com/ and type "10am UTC+10 in UTC-5", problem solved.The thing is you'd have the same problem if the whole world was on the same clock. It would be even more difficult since we'd lose all time references we have (noon, midnight...)