Why were many Greeks poli unhappy with Athens in the years preceding the peoloponnesian war?

The Greeek Poli was unhappy with the Athens in the preceding years of the Peloponnesian War because the Athens became the supreme naval power in Grece. It created the Delian League to ward off possible Persian attacks. ... This power made the Athenian policy makers arrogant and intolerant with other city-states; creating a discontent of the Greek Polis.