Quick thought #1 about Hellenic unity: The Greeks usually dropped their political differences to compete in athletic contests of which the Olympics was only one event. Apparently their zeal for sports and religious festivals sometimes outweighed their desire to annihilate one another.
Quick thought #2 about time, space and ‘sense of world’ for the Greeks:
Their boundaries for the geographic world were much smaller than ours. They thought of the world as extending from the Straits of Gibraltar to India (West to East) and from Africa to perhaps northern Europe (South to North). Therefore, journeys like Homer’s Odyssey were conceivably considered trips ‘around the world’. Hindrances to travel both on land and sea drew out the voyages and exaggerated the mental distances that we take for granted today.