Say good and the antonym shoots back bad. That's the sort of word it is: oppositional, defiant, difficult. It must be tough on the thesaurus, parenting a pack of antonyms.
The synonym, on the other hand, plays well with others. Say good and it chimes in with pleasing, lovely, delightful. Warming to the subject, it goes on: ripe peaches on a sunny afternoon, sliced over buttery batter, baked up sticky sweet. Perhaps a spritz of lemon, a spatter of sugar, a shake of cinnamon.
And here, the grammatically correct cook pauses. She savors cinnamon, practically a homonym for synonym, and shorthand for perfect finish to the perfect summer dessert.