In the movie, George has his two greatest moments ever. First:
George:"No! SIR! Mr Spacely!"
And immediately afterwards, he risks death and dismemberment by entering the machinery to shut down the drill that is killing the Grungies.
In what combines as this and a Tear Jerker in real life, George O'Hanlon, then greatly impaired due to partial blindness and short term memory loss from a stroke, struggled on to play the role of George, managing to finish his final line just before passing away in the recording studio. Hanna-Barbera alum Iwao Takamoto related the moment in the book My Life with a Thousand Characters.
In the series we have Rosie, in her debut episode, dumping a pineapple upside-down cake over Mr. Spacely's head after he yelled at and fired George in front of the family. He later apologized hired George back and even gave him a raise so he could afford to keep Rosie, noting she made the best pineapple upside-down cake that he had ever been clobbered with (he was revealed to still be eating it).