Good Table Manners (1951)

Chuck, a young loner, is invited by a neighbor to a dinner party, but turns it down. He finds himself visited by "Chuck of the future"--himself at age 21. "Chuck of the future" knows the reason the current Chuck doesn't want to go to the party--he's embarrassed over his poor table manners. "Chuck of the future" decides to give "Chuck of the present" some tips on proper table etiquette.

Unfortunately the movie Good Table Manners is not yet available on HBO Max.