Sorry ChickPea!
I know this thread is kind of finished, but I was just thinking about what Falconius said, and it occurred to me that if you were living before Pythagoras (who it was that first declared the Earth to be a sphere) it would be a reasonable assumption to make.
Back then, you see, they could only travel as fast as a horse or camel could run, or a boat could sail, and they didn't have clocks that worked independently of the sun, the moon and the stars, so the time zone difference between East and West would not have been apparent to any of them because it would always be the same time of day for travellers as it was for the rest of the folk wherever they happened to be at that point in their journey. In addition to that, it would have been very unlikely for the average man to have gone far enough from home to realise that there is no mythical 'edge' to the world where the oceans fall off the world in a humungous never-ending waterfall, and even if the average man had the time to think about the impossible nature of the edge of the world back then, it would probably only have been a fleeting thought, since a large portion of the population would have been far more concerned about planning how to make it through from one harvest to the next, and making stores of food 'just in case' to have been concerned about the large scale mechanics of the Earth.
So, yes, I can see how the majority of the people initially believed the world was flat, back before 500BC, and having believed it all their lives they taught their children the same. It must have been quite difficult for Pythagoras to convince an entire nation that they were wrong - not when he couldn't prove it. His theory was rather tentatively based (compared to modern scientific theories) on the curved shape of the terminator line between night and day on the face of the moon. Having theorised that the moon was actually a sphere, he still couldn't prove that the Earth was similarly spherical. It was merely a logical extrapolation of his observations of the moon to suggest that the Earth was similar in nature.
If the Earth didn't have an unusually large moon where the terminator line could be easily observed by the naked eye, a spherical Earth theory might not have arisen until relatively recently - say, around 1520 when Ferdinand Magellan circumnavigated the globe, or even later than that, in the 1600s when the first telescopes were invented for us to be able to observe the terminator line on the other planets in our solar system.
However, I do agree that with global air communications, and the fact that the curvature of the Earth is observable at ground level through the oceanic occlusion of the beach at Dover from across the English Channel, where only the tops of the cliffs are visible from France on an extremely clear day due to the curved 'mound' of water between France and England, you could legitimately call a continued belief in a flat Earth something of a folly.
I do also believe, however, in the right of every individual to believe in whatever they want to believe in, just as long as it does no one else any harm by way of consequence - especially if it happens to be a belief which the majority believe to be scientifically flawed.
EDIT: Here is a thread that shows a lovely picture of the cliffs of Dover from France, and explains why you can't see Dover beach from France - the occlusion caused by the curvature of the Earth which I mentioned earlier.