I fucked as many shepherds as the sheep you herded

A Turkish proverb. Used when someone is acting know-it-all against someone else that actually knows it all.

'Ben senin güttüğün koyun kadar çoban siktim'

The know-it-all: I have recently read a few articles about X online, so I think I am kind of an expert on the subject now!

The expert: You know I have a PhD in X, right? I fucked as many shepherds as the sheep you herded!