Everyone's saying "oh my, I'm so ashamed of my code I wrote 4 days ago, it's so horrible"

Well... At least you can relate to someone. When I look at my project's code I wrote half a year ago (or sometime before that) I'm genuinely surprised to see I'm not browsing some library's codebase - the abstraction layers, the generics, the structure... it's brilliant! It's as SOLID as it gets.