The stairway syndrome is actually an American translation of the French l'esprit d'escalier; that is, the brilliant reply to an insult that you think of a little too late, on the stairway back to your apartment. All of us have probably been bitterly insulted at least once and left without any clue of what to say. However, there is one response which almost always works: it can be said to dry insults, cynical asides, sarcastic comments, but works best when sweetly offered a response to someone's enraged tirade. Very simply, put on a beatific expression, and wait for the person to have their say. Then respond with "You hate me in vain, you know. I'm blessed with good luck!".
There is no answer.