I really like, and use "Because we are adults: potty trained and college educated."
Originated with Cody and is more fully explained during the Horrible Monster Brainwashing PCs-gate.
Also layers upon layers, and the resulting tapestry are also in Fear of Girls:
My new fav however is "Goddamnit Jason." Sometimes it is other people, but mostly Jason said by whoever is GMing at the time.
"He's like Lex Luther x10!" For Axegore the Ogre slave trader for filing suit against the PCs.