About 20 or so years ago, I was working at Microsoft and decided to see if I could find a bug in Notepad. With a bit of playing around I actually got it to crash with an access violation by doing something like scaling the font to a gigantic size, then print(preview?)ing it. Coincidentally, around the same time I attended a small talk by the guy who was listed as the current dev owner for it, so I tapped him on the shoulder afterwards and told him about it. Before listening to the repro steps, he assured me with complete confidence it was not a notepad bug and that I should go step through it for another look. I did, and he was right, it was a bug in the user mode part of the printer driver.