[FromHoiPolloi]

In addition to what others have said - one way to gain knowledge of oneself is to try to understand your feelings and emotions in certain situations. You can practice this by writing a diary where you list your emotions throughout the day.

Sth along: "I felt ______ when _____ happened." or "I felt_____ in ______ situation".

This can give you a better understanding on what makes you happy/sad/angry - from there you can analyze WHY. We are not machines and emotions play a big part in our lives. This does not mean we have to be governed by emotions, but it's healthy to acknowledge them.