“Carved on the temple [at Delphi] were the exhortations "Know yourself" and "Nothing too much," mottoes with a similar meaning: You are only human, so don't try more than you are able (or you will pay the price). A recurring theme in Greek myth is the man or woman who loses sight of human limitations and acts arrogantly and with violence, as if immortal. And pays a terrible price.”
Book:Classical Myth