Were you watching this video by any chance? https://www.youtube.com/watch?v=h7apO7q16V0 ("The Fast Fourier Transform (FFT): Most Ingenious Algorithm Ever?" by Reducible)
"You feel a sense of wonder. A sense of awe at the
elegance of such an algorithm. It happens to not
actually by that useful or efficient as a matter of
fact. But we still study it just as we like to read
a work of fiction. It inspires us."