I've told the same story multiple times but the subject of "painfully incompetent co-worker" just comes up so often.

I have one coworker who never really grew out of the mindset of a college student who just took "Intro to Programming". If a problem couldn't be solved with a textbook solution, then he would waste several weeks struggling with it until eventually someone else would pick up the ticket and finish it in a couple days. And if he found a janky workaround for a problem, he'd consider that problem "solved" and never think about it again.

He lasted less than a year before he quit and went off to get a job somewhere else, leaving the rest of our team to comb through his messy code and fix it. Unfortunately, our team is mostly split across multiple projects and our processes were kind of a mess until recently, so his work was a black box of code that had never been reviewed.

I opened the box and found only despair and regret. He was using deprecated features from older versions of the language to work around language bugs that no longer existed. He overused constants to a ridiculous degree (hundreds of constants, all of which are used exactly once in the entire codebase, stored in a single mutable map variable named "values" because why not). He didn't really seem to understand DRY at all. His code threw warnings in the IDE and had weird errors that were difficult to reproduce because there was just a whole pile of race conditions.

I ended up having to take a figurative hacksaw to it, ripping out huge sections of unnecessary crap and modernizing it to use recent language features to get rid of the deprecation warnings and intermittent errors. And then I went through the same process again for every other project he'd touched.

Good riddance.