Spinach Packin' Popeye (1944)

Popeye donates blood, then dashes off to a boxing match with Bluto. He loses. Olive, who heard this on the radio, rejects him as no longer strong enough for her, and is preparing to join the army (where Bluto apparently is). Popeye stops her at the door, and insists on showing her sequences from two earlier two-reelers to prove his strength, but she's unimpressed. Fortunately, this was all a dream; he awakens in the blood bank, and dashes over to see Olive, who reaffirms her love.