Because the Greeks do not like to acknowledge someone’s power over themselves. In this connection, Greece was not a single state, but was divided into many policies. When the enemy came to the Greeks from another country, they immediately united against him and fought until he was defeated. A similar situation happened with the Persian Empire, which invaded Greece in the 5th century BC..
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.