How important is it to have things in common with your group of friends?

I guess there’s general things you can have in common like music, books, films, art. Things that are nice to share. That also sort of leaks into how you like to spend your free time, your hobbies. Then there’s values, moral compasses, that can also be tracked back to the above -what you consume and how you spend your time.

What if one thing, like schooling or being in a particular program brings you together but after awhile it becomes apparent that something’s shifted?

I guess what I’m trying to ask, is what is the glue of friendship? Do common interests matter? Is it all chemistry? What is it?