Related to this is one of my favorite articles: https://www.theatlantic.com/magazine/archive/2003/03/caring-.... A year ago, my wife and I ran into a friend of hers who seemed hard to get to know better. On a hunch, I pulled up this article, and she scrolled through it and was like "yup, yup, yup, yup". She hadn't been able to articulate that for herself.
A related book is https://en.wikipedia.org/wiki/Quiet:_The_Power_of_Introverts.... The title kind of says it all.