Happiness is a hard-sell because Happiness is a self-generated emotion.
It can’t be forced onto another person the way more negative traits like Fear, Sadness, Greed, Regret, Inadequacy, etc. can.
Everybody has their own ideas of Happiness -a roomful of books, lots of money, a large family, quiet time with nobody around, God, oblivion, job security, Summer holidays, etc.
But you only have to mention DEATH and your entire audience is united in Fear. Stick a few murders on the pot and you have a guaranteed audience of headlighted-rabbits.
Death, like Sex, is an easy sell. Too easy in my view.