What makes you happy when you are sad depends on the kind of sadness. Sadness comes in different forms and what I applied to change my mood positively are biscuits and music.
I have learned never to let someone control my mood while he goes happy doing his usual things while I am being angry but rather to control my feelings, words, and action toward someone.
How Biscuit comes to work
Biscuit help me out when am bordered on a particular thought, maybe what someone told me and trying to find a way out of it, when my team Barca loses the match I wanted them to win, when am angry with somebody and just want to get over it and regret on my past attitude which is flashing through my thought every second. Biscuit has helped me to conquer fear, tension, and sometimes I called it my best "Friend".
Music
Music is my soul healer, mending my broken heart and making me realize that life is the true story of every leaving being, spend it with worthy people and those who come your way. Financially when am broke, listening to music gives me hope and joy for a better world even if it doesn't give me physical cash at that moment. Relationship comes with side effects as our feelings get hurt by others, I listen to music and move on loving and finding many reasons from songs to be happy through their wordens, musical instruments particularly Guitar.
I listen to most kinds of music either hipop by Tupac songs my mentor, worships songs, etcetera.