Glitches that result when we forget the physical nature of computers. Or, office chairs, iPhones, and helium.
When I first was introduced to computers we had an IBM 709. It was a tube machine and shortly before it was replaced it began having very transient glitches. It was driving everybody up the wall, especially a good friend of mine who was the resident IBM engineer. It turned out. that the circuit boards around and above the thousands of tubes had been slowly boiling off silver from the wire traces on the circuit boards. When they re-condenced (like fog on a cold mirror in a bathroom after a shower) on the circuit boards they again were able to conduct electricity. Very periodically they would either add or drop a bit. I don't know how the problem was finally solved because I graduated and left for parts East but the next time I came back there was a brand new 360/67 in it's place.
Nice. The Funny Programming Languages article is great. "If fewer than 1/5 or more than 1/3 of statements are prefixed with PLEASE, then compilation raises an impolite/too polite error." Hilarious!