Didn't you have your Wheaties?
Used to ask why somebody is not working as hard as they should, inspired by the fact that the cereal of the name is supposed to help one build big strong muscles. Coaches especially like to ask this of their players, when their players are not practicing nearly hard enough.
"Didn't you have your Wheaties?" Coach Egan asked of David and Greg,who were horsing around during football practice. "You're supposed to be practicing and putting lots of effort into it! No horsing around!"