I do believe that if you haven't learnt about sadness, you cannot appreciate happiness.
~ Nana Mouskouri
For my convalescence, I had to exercise my voice only with vowels. It is a medical rule after a long loss of voice.
If I was sad or afraid, I would sit in a corner and sing. If I was happy I would jump into the middle of the room and sing. It was how I expressed my emotions.