I just wish python had some better ergonomics/syntactic sugar working with itertools and friends. Grouping and mapping and filtering and stuff quickly become so unwieldy without proper lambdas etc, especially as the typing is quite bad so after a few steps you're not sure what you even have.

Just as recent as today I went to Kotlin to process something semicomplex even though we're a python shop, just because I wanted to bash my head in after a few attempts in python. A DS could probably solve it minutes with pandas or something, but again stringly typed and lots of guesswork.

(It was actually a friendly algorithmic competition at work, I won, and even found a bug in the organizer's code that went undetected exactly because of this)