Spartans were known for their warfare tradition. They didn't care much about their neighbors unless they needed something from them. Usually, when they needed land for new settlements they would attack the neighbors and take their land as prize for their victory. They would also often enslave the losers which was common at the time. They despised Athens because Athens was strong and had a lot of political power. This is the reason why eventually the Peloponnese wars broke out and how Athens started losing its domination of the region.