Who knew?

What would happen if we only had one time zone?

You may be eating lunch in total darkness.
The Earth rotates on it's own axis around the sun so different parts of our planet are exposed to the sun at different times.
 If we only had one time zone, then 12 noon would be middle of the day in one country but the middle of the night in another.
 By having different time zones, nobody will get confused with the meaning of day and night.