esprit de l'escalier(Used to refer to the fact that a witty remark or retort often comes to mind after the opportunity to make it has passed. ‘Now if I'd managed to say all that off the cuff then I would be a genius comedian, but as it was I had to make do with experiencing esprit de l'escalier on the way home.' ‘I am frequently afflicted with esprit de l'escalier.' Origin French, literally ‘wit of the staircase' (i.e. a witty remark coming to mind on the stairs leading away from a gathering). oxforddictionaries.comAlexander Demidov)
