the germans call it treppenwitz
it means thinking up of a clever comeback shortly after the moment has passed.
like after you got shut down and you were left speechless, then as you're walking down the staircase towards the exit or as you're driving home reminiscing about the night, you come up with the perfect comment you should have responded with. but the moment has passed.
the bigger problem is avoir l'esprit de l'escalier. The "avoir" makes it like an infirmity you posses. it means time and time again, you only come up with that repartee as you're walking down the stairs towards the exit. you're always a few minutes too late.
i'll do all i can to prevent this from becoming the story of my life.
i'll write all my lines the night before if i have to.