Everyone is a genius. But if you judge a fish by its ability to climb a tree,

 "Everyone is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing it is stupid."

— Misattributed to Einstein

Explanation:
This powerful metaphor teaches us that people shine in different ways. Genius isn't one-size-fits-all. Recognize your unique strengths rather than conforming to societal norms.