This happened towards the end of a data archival project I was involved in.

It was the last day of the project and we were in the process of handing over the system to the client. As it so happened, the client, while doing a sanity check, found out that some unwanted data had not been deleted from the database.

On project manager said to us, "Let's delete the unwanted records manually."

The only problem. There were three of us and over 150000 entries to delete (the system had around ten years of data).

In the end, we came up with a logic to identity the unwanted records, and I created a small program to delete the entries using this logic.

To this day it is still not clear as to what inspired the PM to come up with such a suggestion.