"Wish I didn't know now what I didn't know then"?

Nope, the opposite...  the old standard "wish I'd known that then".

This is a forum about beliefs and ways of thinking, so what do you wish you'd been told, way back before you started exposing your shortcomings on a public message board.   (Oh, yes, we all do - even the most dogmatic and confident!)

Mine?   Its hard to argue with people who just know they know; its impossible to argue with people who don't know they don't know.