Such thin lines between those two. I realized I never really categorized any feelings or situations im in, as either happy or sad. I prefer comfortable or not comfortable. Why? Cause most of the time I feel comfort in sadness, yet total uncomfortable awkwardness in happiness. I have came upon some analysis about this phenomena that I (and I'm pretty sure a lot of people have experienced).
One, is because some people and I have experienced particular things in life that taught us not to have high expectation so we try to keep the life low. Keep the life regular, that way happiness is cheaper. Two, is because some people and I think that happiness is so overrated. Life is all about struggle, it always have, always been and always will. Three, is because some people and I think that sadness is the only feeling deserved after all. See, the fact that everyone thinks that life is unfair actually makes life... fair. Ketidakadilan adalah keadilan tertinggi.
Anyways, those are just hypothesis not theories. Maybe it's just me.