This is maximum Dunning–Kruger effect right here. This is how you end up with cowboy code nobody but you can debug. You'll spend all day bragging to everyone on Twitter about how you can put "big data structures in your head" meanwhile you're spending hours manually testing things that only require 10 seconds of the full test suite. Then over the next 2-3 years, random things break between releases unless you're QA team is doing hours of regression tests all the time.