&quot;But sarcasm comes by definition at the expense of an idea or another person.&quot;<p>Even to the extent that is true, which I could quibble with, the sarcasm can be at the sarcastic one&#x27;s expense, as a form of self-deprecation, or it could be at the expense of a person not present and one who may not even properly-speaking exist.<p>Sarcasm at a coworker&#x27;s expense isn&#x27;t wrong because it&#x27;s sarcasm, it would be wrong because <i>any</i> social interaction at a coworker&#x27;s expense is generally wrong.