It's difficult to say, as I cannot know the whole situation to find the worse thing, however a pretty bad thing to say to someone who's been fired is: "What are you looking at? Get your things and get out of my face!".
It's important to note this is only relevant to say right after firing that person.
spam fails_task lang_mismatch pii not_appropriate hate_speech sexual_content quality toxicity humor helpfulness creativity violence