The real phrase is, "The quick brown fox jumps over the lazy dog", and it's a typing excercise that uses all 26 letters....go ahead....count them off.
as useful as typing "computer" a thousand times over
no matter how many times you practice, you'll never type "z" very efficiently
so give it up
... please don't fire me big boss man
... I'm sorry I lit your house on fire
... electrostatic shock is a serious concern for hackers the world over