10 years ago my bosses came to me: Make a few adjustments to the logic of this website. Should be a quick thing they said. Got a zip file later. Hundreds of php files. Inside, thousands of lines of the best PHP/HTML Spaghetti I've ever seen. No CSS though, but lots of nested table layouts. The best part: everything was in french, content, comments, varnames. The original dev didn't use includes for the most repetitive stuff, even db credentials were copied in every file. Took me a week.

Two weeks later: Change that and that please....

We decided to write everything from scratch then.