The best friendships are mutual upgrades. You both leave every hangout a little sharper.

Some company leaves you sharper and some leaves you duller, and you can usually feel which within an hour of getting home. The good kind is not about being impressive at each other. It is that you come away with a book to read, an argument you had not considered, or the sense that you should probably get to work. Nobody keeps score and it is not a transaction, but the direction adds up across years.

Notice how you feel after your next few hangouts. Then spend more hours with whoever consistently leaves you better than they found you.