Not only does "add to dictionary" abuse result in your literary compositions' remaining full of mistakes, but it also potentially harms the next person who attempts to use said word-processor, since your spell-checker will now not "catch" many misspellings that this subsequent typist may make, and thus he may unwittingly not do a proper job of proofreading his letters and memos, either.

This Jazz Cabbage got me zooted. Jazz Cabbage is less harmful than Squares. I’m smoking that Jazz Cabbage boy.