I did the same thing for years. What helped was setting a rule that I can only buy a new game if I've played everything I own at least twice, and if it's been sitting untouched for six months it goes in the trade pile. Sounds strict but it made me way more picky about what actually earns shelf space. Now my collection is smaller and I play almost all of it instead of staring at a wall of shrink wrap.

Colon vs semicolon trips people up way more than it should honestly. What I want to know is when you went back and stared at line 12, what finally made you see it? Were you comparing it to a working line right above it, or did the Real Python article show you the exact spot? Because in my experience the answer is usually you have to retype the whole line by hand instead of just looking at it. Your eyes skip right over a tiny dot when you already read it once and decided it was fine. So did you fix it by retyping or did something in the article actually teach you a system for catching it?