Bad moods can actually be good for you, with an Australian study finding that being sad makes people less gullible, improves their ability to judge others and also boosts memory.
The study, authored by psychology professor Joseph Forgas at the University of New South Wales, showed that people in a negative mood were more critical of, and paid more attention to, their surroundings than happier people, who were more likely to believe anything they were told.
Put this in a box with a growing body of researching indicating that there’s a problematic relationship between what’s good for you to think and what’s accurate. For example, how well you fare in life is largely due to socioeconomic circumstances and luck. But individual initiative does play a role. And consequently people who overestimate the role of individual initiative tend to do better in life than those with more accurate perceptions, plausibly because getting this stuff wrong inspires you to try harder. There’s also a substantial literature on “depressive realism” indicating that people suffering from depression have more accurate perceptions about many things.