This is an early example of the periodic catchphrase 'Why you little', which the Simpsons' writers go on to use many more times. It is often a prelude to stranglulation, and this scene is no exception.
Check out the FULL PLAYLIST of Simpsons Catchphrases:-
/playlist/PLozDrbEuzBfCGM_Ov9CIJnrt7LK_e6RyJ
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