I once had this situation when I forgot what it feels to be happy. It’s not that I can’t smile and laugh. I just feel okay and fine but I don’t know if I’m happy. Until I realized that It is because I want the exact same thing to happen again; those memories that made me happy before. When I’m feeling really depressed about it, I suddenly think that it’s because I treasure it that much and It makes me feel like it’s the only stuffs that can make me happy ever again. That’s how I remember that we should treasure every moment in order to be happy.