That guy

So...yeah. It's my mistake. I leave my door open (literally).
When polite conversation produces the phrase, "How are you?" and YOU, SIR don't know me aside from our regularly awkward exchanges, it's appropriate to say, "Fine, thanks." Even, "I've been a little under the weather" would be perfectly acceptable. Then it is my choice whether to inquire after your ailment or simply let the moment pass with a "that's too bad" or "well, I hope you'll feel better in time for the Holidays."
Mr. Scarfaroundhisneckbecauseit'scoldtohiminthisoverheatedbuilding describes the "crud" in his throat and the fact that the doctor can't do anything about it. And I didn't ask.