I am not sure where or when this happened, but I still think there may be some truth to the story.
Once someone from the engineering (or physics?) department of some university went came to see Joseph Bernstein and asked if he knew a formula for a conformal mapping of the interior of a regular $n$-gon to the upper half-plane. Bernstein knew the formula, but decided to first ask what the person needed it for. The reply was: "Well, you see, what I really need is a formula for the unit disk, but that's probably too complicated, so I decided to find out the formula for the $n$-gon first and then take the limit."

