Mr. Warren is Frank's boss. He makes Frank jealous because Mr. Warren has three boys possibly about the same age as Rodrick, Greg, and Manny who love sports. Whenever Frank is riding on his carpool from work, he sees them in their front yard doing many manly things. Frank doesn't like looking bad in front of Mr. Warren and usually will get worked up if he does. For example, in Diary of a Wimpy Kid: The Last Straw on Easter when Greg said he didn't want to go into church because of all the chocolate on his pants, Rodrick took his pants off and offered to let Greg take his and at that moment Mr. Warren drove by which made Frank pretty upset.