New Insights into Self-Insight: More May Not Be Better
scientificamerican.com
scientificamerican.com
There's a well-known phenomenon whereby narcissism and self-evaluation is generally related to positive mood. It's part of an overall positive tint.
So one interpretation of this is that people who tend to be optimistic also tend to just feel better in general, for whatever reason.
It's not clear to me these "benefits" would transfer to all scenarios, nor is it really clear that it's about insight in general in the way people usually understand it.
Whatever we're doing has to be making individuals more mature to be valuable.
Whether this research is a bug or a feature remains to be seen.