:) Personally I've never used any serious complex analysis in my job (I'm very grateful too, because I always struggled a bit with it). The closest thing I've seen, which I did run into recently, is the use of complex numbers to compute very accurate finite differences. It's one of those delightful tricks that is both elegant and useful: https://blogs.mathworks.com/cleve/2013/10/14/complex-step-di...

I've been working in golang, which fortunately has built-in complex128 types, so it's proved very helpful in a project!

oh cool, I really like Cleve Moler's Matlab posts.

I took a complex analysis class and did OK, but I get the feeling that EEs are the ones who really benefit from it (at least in the applied world). They seem to have some very rich analyses of linear dynamical systems using frequency domain methods.