Tim Bray shares the cautionary tale of Susan and her SQL Problem:

As usual, it all started out innocently enough. Susan [ed: names have been changed to protect privacy] had no way to meet the deadlines her bosses had set for her. Bob had recently and abruptly left the company, and Melissa was on an extended medical absence, leaving Susan to do the work of three people. That is, three people each trying to reconcile a few dozen 40,000+ row Excel spreadsheets representing the general ledger of the Fortune 1000 company they consulted for. She was about to brush off ever-chatty and annoying Michael from Compliance when, for once, he recognized the stress she was under and said something useful.

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Useful and dangerous, that is.

"Hey, let me give you something that'll help. A friend introduced it to me, and it's made my life amazingly easy ever since," he said. He handed her a USB stick. […]