For me the definition of good vs evil are just your good emotions vs. your negative emotions.
Now I've looked extensively into this subject and came to conclude all negative emotions come from either
judging or controlling thoughts towards people or yourself. For instance, the more you hate someone, the more those thoughts begin to make you feel bad.
As for good, these are just the opposite of your negative emotions. So instead of controlling thoughts, you give people thoughts to achieve freedom and trust. And instead of judging thoughts, you give people thoughts of gratitude and compliments. Both freedom, trust and appreciation towards another will enable you to love each other and feel that 'good' feeling.
Stevie B