My colleague once wrote 160 lines of ruby code that violated rubocop in 102 lines (and he thinks he is a "clever" senior)

This is true I swear... I once worked on part of a project "optimization" that required, running a job on sidekiq in the background that spawns multiple threaded RPC calls on RabbitMQ (and be I/O blocking) till the jobs are done (or failed) so that it updates the status of the master object (that has the associated objects processed) and sends an email to the ops manager (just a summary email)... instead of using database locks... or dropping the email requirement...

I did it without arguing because I've already quit the job a while ago...