I remember the lightly-accented words of my word-loving cosmopolitan immigrant father, telling me this joke in the early 50’s when the words were still current:
FATHER: There are two words I want you to promise never to use: One is “swell” and the other is “lousy.”
SON: Okay-Doke, Pop, what are they?
(His mispronunciation partly missed — and so unwittingly made — the point.)
He also asked me to promise never to play jazz on my horn.
(My grandmother asked me to promise never to marry a gentile girl.)
I kept both promises, unwittingly, one by giving up the horn altogether, the other by never marrying at all.