We're really bad at knowing how we—ourselves—think. We're also bad at knowing how others think. What results is tribalism, where we over-estimate our ability to accurately model mental states and motivations of others.
Mindwise had many incredible perspectives and nuggets of information. If our greatest skill is to be able to understand the minds of others and ourself, it's vital that we intentionally seek to improve this ability.
The book paces well, and has great insights the whole way through. I highly recommend it.