“From then on, when anything went wrong with a computer, we said it had bugs in it.”
On the removal of a 2-inch-long moth from the Harvard Mark II experimental computer at Harvard in 1947, as quoted in Time (16 April 1984). Note that the term "bug" was in use by people in several technical disciplines long before that; Thomas Edison used the term, and it was common AT&T parlance in the 1920s to refer to bugs in the wires. Hopper is credited with popularizing the term's use in the computing field.