Carved into the walls of the ancient Greek temple at Delphi were two proverbs: γνῶθι σεαυτόν ("know thyself") and μηδὲν ἄγαν ("nothing too much"). Plato mentions them in his dialogue Protagoras, set around 434 BCE, but most likely they were common among the Greeks as far back as 600 BCE or even earlier. Although they are so very old, recently I've been pondering their connection to the latest research in the modern science of psychology.
First, consider "know thyself". This has clear applications to personality psychology. In order to make use of the relevant scientific insights, you need to not only understand the theory but complete a valid, reliable personality inventory (preferably based on the five-factor model), and then reflect on how those personality traits are expressed in your attitudes and behavior. This gives you a store of self-knowledge that can guide better choices and decisions in your life.
Second, consider "nothing too much". The Positive Psychology movement has identified a number of character strengths that show up across most or all human cultures, and has created inventories that enable you to identify your greatest strengths. Although it might sound ideal to cultivate and leverage your strengths (say, empathy) at home and at work, psychological research has shown that it's all too easy to overplay your strengths. As one example, if all you do is empathize with others then you might accept mistreatment in an abusive relationship, overlook ethical lapses by your co-workers, or neglect to insist on effective performance by your employees. Too much of a good thing, indeed.
It strikes me that there's a tension between these two proverbs, because a key foundation for the rise of ancient Greek philosophy was the idea that you can never have too much wisdom or self-knowledge. But that's a topic for another day...
(Cross-posted at philosopher.coach.)
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