So you want to help people? That’s great — but beware the law of unintended consequences. Three stories from the modern workplace.

The psychologist Daniel Kahneman — a Nobel laureate and the author of “Thinking, Fast and Slow” — recently died at age 90. Along with his collaborator Amos Tversky, he changed how we all think about decision-making. The journalist Michael Lewis told the Kahneman-Tversky story in a 2016 book...