Hang a wall plate
A reference to the popular video "Haters Don't Hate" by comedian Bridget McManus. Meaning: "get over yourself" and/or "don't be so judgmental". Basically, just don't be a hater.
"Man, I'm being such a hater, I should hang a wall plate."
"You really need to hang a wall plate!"
"You really need to hang a wall plate!"