Why do you think Greek trade routes usually followed coastlines?

Being that Greece resides on the Agean archipelago, it made sense that trade routes followed coastlines, since most city states resided by the sea. The Greeks were able to utilize the sea for good staples, but it also served as a way to expand influence, culture, and trade. Intellectual discoveries also were transmitted between port cities. The sea may have also held religious significance to the Greeks, exemplified by some of their deities like Poseidon.