A colleague accidentally deletes some critical document files from a computer while doing a job for the Cow-orker that she hadn't been able to figure out herself. While he beats his head against the desk in frustration and self-recrimination while swearing that he thought he'd done everything correctly, the Cow-orker excitedly tells everyone how she knew it was a mistake giving that work to him to do, and that she knows he didn't do everything correctly.
And how can she be so certain?
Because she was looking over his shoulder telling him how to do something she didn't know how to do herself, while winding him up about something at the same time for good measure.
