Why did athens become so aggressive with its neighbors following the persian wars

Athens acquired superiority of all the Greek states than Sparta due to its strong naval base.

Explanation:

After the Persian wars, Athens emerged to be victorious and they started to rebuild the city of Acropolis. They used all the bronze in the weapons which were used in Persian war to make the statue of Athena. Sparta became jealous of the Athenian victory.  

Spartans had lost much in the Persian war and the economy became unstable. Out of envy, Spartans also tried to attack Athens in order to gain power.  

the second significant cause of the great migration was the desire of black southerners to escape segregation, known euphemistically as jim crow. rural african american southerners believed that segregation - and racism and prejudice against blacks - was significantly less intense in the north.