What's your opinion on the theory that happiness is a construct with no biological basis and humans aren't designed to be happy?

Sounds like the same type bullshit theory of a cranky person that comes up with the idea that screaming that "Santa isn't real!" in front of the line of kids waiting to see him in the mall, because "We shouldn't lie to children".

It's bullshit. They aren't happy, so no one should be happy.