The story told to me by my set theory teacher back in college was that a Paul Cohen was an Analyst who attended a symposium on Set Theory and said "hey, this is all the set theorist do? This is easy!". He then switched his field to Set Theory, developed forcing, and proved a bunch of important open questions in the field.
I don’t know if it’s true, but I’d like to believe.
He was drawn to logic by discussions with Feferman and worked unsuccessfully on other problems in logic before moving to independence questions in set theory.
I've heard a version of this too. With the additional details that after the result was announced, he struggled and took quite a bit of time to get it ready for publication.
I don’t know if it’s true, but I’d like to believe.