Warren was the rude patron in the restaurant at the beginning of the Season 5 episode Both Sides Now. He was with his girlfriend Paula and was complaining to her about the food. He was portrayed by actor Scott Conley.
When Scott's left hand starts throwing dinner rolls at him, Warren tries to pick a fight despite Annie pleading with him to stop. when Scott's right hand shakes hands with Warren to try to make peace, Scott's left hand pours cold water on Warren. Warren stops shoving Scott when blood starts running from his eye.