Doughboys (1930)

Elmer (Buster Keaton) is a privileged and affluent young man who has never wanted for a thing in his whole life. Then he falls for a beautiful USO performer named Mary (Sally Eilers), who finds his lack of concern for his fellow man deeply appalling. After Elmer mistakenly enlists in the military, he is offered a second chance with this lovely lady, though he has some stiff competition in the form of the suave and tough Sgt. Brophy (Edward Brophy).