It couldn't be that Kahnemann made a beginner's mistake and interpreted a ceiling effect in his outcome as a moderator. No, "conventional practice" dictated labelling the outcome variable happiness, rather than unhappiness.
Tenure is one hell of a drug.
https://www.pnas.org/doi/10.1073/pnas.2208661120
why can someone who is heartbroken at an income of 10k buy an ice cream cone and be happier, but someone with an income of 110k just cannot alleviate his heartbreak with ice cream and a nice spa visit