We still need tons of empirical backing here
This observation is obvious (insert stuff on the nature vs nurture debate here), but we need to remind ourselves of this fact when choosing the influences we surround ourselves with. Goethe said, “We are shaped and fashioned by what we love. This notion is heavily echoed in Book - Steal like an artist.. 10 things nobody told you about being creative to argue that our own artistic output always is a aggregate of the things we consume.
The "you are the average of the five people you surround yourself" is probably social media fluff, but I recall there being research on obesity (check out the book # Friend of a Friend . . .: Understanding the Hidden Networks That Can Transform Your Life and Your Career)