When you stand under the sun(light), one side of you might be bright
While the shadow on the opposite side might be a bit dim or lack of light
I think this might be an appropriate condition that can be taken into account
When explaining Positive or Negative emotions that  you may feel you are set upon

I mean if you choose to see only the bright side that's often with you along 
You may feel happy as you think you are warm, active, soft  and giving out light
So often remember to look for the things that may make you feel pleased or fond
And choose to go to persons who might be willing to Praise you or to say "you are right"
Also, value and pursue "any opportunities" that may  lucky you with a good fortune
And treasure and nurture "any reasons" that  leads  you to say  "I am very well done"

To make all aforementioned easy to be true  to let them to bring you positive mood
You have to remember that you should  firstly learn how to cultivate " a heart of Gratitude" 
And then to  love, respect,  and help people who are wanting positive moods as you do