You are more powerful than you realize

It always bothers me when writers feel the need to expand upon a character’s powers.
How many comics can you think of where some “wise man” tells the hero he has more abilities than he believes he does?
If
I had superpowers, you can bet I’d be exploring them all the time, and
not wait for some hermit to tell me how to “flip the switch” on more
powers. No one would know me better than myself.