True friendship is when you can be together and not feel the need to entertain or be entertained.
Many people who self identify as extroverts are just deathly afraid of silence and isolation as it may lead them to pay attention to their own thoughts.
If you've experienced true friendship it becomes painfully obvious who's not very good at this hanging with people thing as you meet new people.
They are going on adventures together! Maybe one day they'll both read the same book at the same time, and go on the same adventure!