What is pocket wisdom?

What is pocket wisdom? The term just popped into my head, & I don’t where it came from.

My girlfriend says:
”It’s the kind of wisdom, that whenever you’re really bored one day, & you’re digging around in your pants pockets for something to, you find down in the very bottom of your pocket. It’s like one of those paper fortune thingies you find in a fortune cookie, & you pull it out, & you read it, & you’re thinking, ‘Hey, that sounds smart!’. And you call it POCKET WISDOM!!!!”

What do you think pocket wisdom is? Because I have no clue.