If you are too conscientious, you might experience undue stress during a negative performance review. Or being too agreeable is correlated with lower salary levels, especially for men. And surely too much extroversion and too much openness are possible too?
…researchers have only recently begun to uncover evidence that extreme standing on “normal” or “desirable” personality traits might be maladaptive…many more people possess optimal personality-trait levels than previously thought…
I don’t quite agree with that, though I wouldn’t, would I? I think they are overrating normality. The notion that “weirdos are bad” seems to me longstanding, and one of the most durable human intuitions, not something that researchers have only started to realize. In a world with growing division of labor, and greater accountability (in the private sector, at least), extreme traits would seem to be rising in social value. And perhaps some of that return can be captured as private value too — Silicon Valley anybody?
Overall, I still think that “falling short” on say either conscientiousness or openness is undesirable for most though not all individuals. How can conscientiousness ever be bad, you might be wondering? Well, if the world is underproducing people with unusual interests and inclinations, more conscientiousness might make “more weirdos” a harder outcome to achieve. For instance, conscientiousness, with respect to obligations toward broader society, might keep many people more conformist. That said, there still are many people who would do better to get up in the morning and go to work, one manifestation of conscientiousness.
Agreeableness is the trait that remains a hard to define black box. Cooperativeness is often good, though simple deference to the opinions of others, without critical examination, is often bad. When I hear “agreeableness” discussed as a formal personality trait, the possible clash between those two (and other) underlying features of agreeableness seems to receive insufficient attention.
Here is a previous MR Post on related issues.