I recently started reading https://www.reddit.com/r/softwaregore/ (the one link I get a day in my email), and it's always interesting.
My favorite video game glitch might be this Super Mario World code injection https://www.youtube.com/watch?v=voL3e0iqugo&t=63s&ab_channel=SethBling ... I was actually looking for the one where they jump to the end credit scene, but this one might be even cooler because he gives himself a nonexistent powerup.
For computer glitches, I had one in mind but I can't find the article. Basically Microsoft had a sophisticated secret way for the Microsoft webpages to elevate privileges in their browser to run arbitrary code or update the OS or something, idr, and someone found a simple way around it that apparently the programmers at Microsoft hadn't thought of, so it was kinda funny.