Early Matlab version(s) had an interesting Easter egg. Once when frustrated with the learning on the REPL, I typed "fuck you" and the console spit out "your place or mine?" instead of an error that I was so used to.
My first project in grad school was a visual perception experiment, written in Matlab. People were shown images that were either just noise (think static or clouds) or noise + a very faint shape, and asked to report which was which. The goal was to analyze the noise patterns associated with each response to identify how people recognize shapes (e.g., do you need all four corners to recognize a + sign).
I tested the task on myself first. It’s fairly late, maybe 9:30 or 10pm, when I finally get everything running just so. Sitting in our pitch-dark testing room, in the middle of a deserted floor of a medical school, I run the analysis code.
I’m expecting to see some simple shapes emerge from the processed noise; I think I used crosses, triangles, and Gabors as targets.
Instead, however, window after window pops up with the creepy, distorted face of that child. I was tired, hungry, and had just seen The Ring, so I did the obvious thing: I slammed the laptop shut and high-tailed it home.
The next morning, my labmate helped me figure out that I had written imagesc somewhere, instead of images, the variable that contained my results.
TL;DR: Typo terrified me.
Edit: I checked it out- Matlab has been around since 1984, and Prof Trefethen was made FRS in 2005. Safe.