To me, as a member of a social species, the metric of "good" is the pleasure I can give to another person. Seeing that joyous reaction and knowing that I gave it to them, that I was responsible for brightening someone's day even for a moment, is my reward. Conversely, actions that cause misery or harm to another person I deem "not good". These are general precepts and subject to situational revision, of course. I may have to lie to someone to spare them from a distasteful truth, or make sure a child takes medication that they need but which tastes bad to them.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'