The first time I added rayon to a project and switched my main `iter` to `par_iter` and it compiled with no other changes was decidedly creepy. That particular code didn't run any faster, but the fact that it was still guaranteed to be safe just felt so counter to everything the last 10 years of programming had taught me. Rust is not a perfect language (whatever that means), but more so than any language I've ever used it gives me these strange sort of mind-blowing moments.