Advice or wisdom passed that offers little or no value to a situation. Typically based on common knowledge that is skewed based on ignorance, or a similar isolated past situation that occurred in a third party's life that has nothing to do with the current situation.
"Cara hasn't called for like 3 hours."
"Dude, she's fucking someone else, probably one of your friends or a close relative. Maybe even one of your teachers from high school"
"Uh, how can you tell that?"
"Totally happened to my cousin's friend, the one that works over at Public Storage."
"What kind of fortune cookie bullshit is that? You're an asshole, my friend."