I also like that it's 3 rather than "list 10". There's some research on this: when people try 3, it's rather easy to succeed. If they try 10, they might find it hard, and if they run out of "good" things to list before finishing, they may erroneously conclude they have it pretty bad.

Psychology is rather funny - good to study it empirically! I'm so thankful there are so many Ph.D. researchers who take it seriously and contribute to the general knowledge by writing books for the general public.