Mrs. Jumbo locking the mean elephants in their stall.
She also smacks a boy for teasing her son.
The ringmaster locking her up was his Moment of Awesome in the same scene. You wouldn't think a human, much less an unthreatening-looking guy like him, would be able to subdue a rampaging elephant, and yet he does.
Timothy Mouse gets his good moment by scaring the other elephants for picking on Dumbo.
The crows teaching Dumbo to fly.
Before that, Timothy's speech calling out the crows and the world at large for mocking Dumbo's ears.
Dumbo shooting peanuts at the mean elephants like bullets from a gun is his way of saying "Take That!"