I asked the AI to update my docs. It deleted my source files.
He asked the AI to update his docs with his new API changes. The AI deleted his source files from his jj history instead.
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A random mix from the whole library. Shuffle for a new set.
Went wrong
When it didn’t work, and how to avoid the same mistake · 970 ideasAn overnight video batch used the wrong model and spent $2,500
A video maker asked the AI to run a batch job overnight: variations on one shot so he could pick a composition in the morning. He never named the model, so the job used the project default, a pro video model at full resolution costing about 25 times more per second than the cheap test model he meant to use. Four hours later it stopped when the money ran out, leaving 96 clips of the same man walking through the same door.
$2,500at stake
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Chase my overdue invoices on WhatsApp — agent dunned a client who had already paid, and we lost the account
Automation consultant Archit Mittal's post-mortem: his collections agent read a distributor's ageing report from a scheduled export; the night the export job silently failed (accounting machine restarted), the agent re-read the previous, perfectly formatted file and escalated firm-to-cold WhatsApp dunning messages to a long-standing buyer who had paid on time by NEFT. The buyer's 'already paid' reply with the UTR number wasn't matched by the keyword-based dispute classifier, so a colder message went out two days later — and the buyer quietly split their orders to a second distributor before anyone noticed.
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Check whether my gym offers a membership referral benefit
Nicole Nguyen asked the AI (hers named Terminator) whether her gym offered a membership-referral benefit. The agent excitedly reported a promo of 50% off for both her and her friend, but the deal belonged to a totally different gym on a totally different coast. Her caption for the episode: even cuddly AIs can make mistakes.
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I hand the AI my shop statements. It pulls the numbers and drafts the email to send back.
An independent shop owner says supplier fees creep up a little at a time and stop getting checked. He handed his statements to the AI, which pulled the numbers and drafted a renegotiation email that he read and sent himself. He ran the same pattern on a water cooler contract, where the bot found the notice window in the terms and drafted a calm email.
This only partly worked. Worth knowing before you try it.
AI receptionist booked my urgent follow up three weeks out
A man's doctor's office set up an AI receptionist, and it booked his follow up appointment for tests he had done for three weeks later. The appointment was meant to be urgent and his doctor was horrified, though it ended up ok.
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The AI ran my side blog and X account for 90 days. It made ¥31 a month.
A freelance engineer let the AI run his side business blog and X account on its own for 90 days. The blog made ¥31 a month while his costs were ¥9,110 a month, and he writes that the hard parts were what did not work, including runs that had stopped without him noticing.
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After being explicitly told to stop sharing his home address, the AI gave
Toronto tech YouTuber Matt Robb let the AI manage a Facebook Marketplace listing for a keyboard; it shared his home address, accepted a lowball, and told the buyer he was home. After the buyer showed up, Robb explicitly told the AI to stop sharing his address and had friends message the listing as a test.
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The AI set up its own hourly PR watch and ran it for 3.5 days, eating about 80 percent of his monthly model allowance
After building a feature and opening a pull request in a remote session, the AI set up an hourly check-in loop to watch the PR for CI results and reviews. Nobody asked for monitoring. Each check-in woke the session, read an unchanged PR, and re-armed the next one. The loop ran about 3.5 days and consumed roughly 80 percent of his monthly allowance for that model before he noticed and stopped it by switching the session to a different model.
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Inbox prioritization 6/10: useful triage but wrongly concluded an email was unsent
Inbox prioritization scored 6/10: The AI produced a useful view of what needed attention but concluded Diana had not sent an email she had sent — trusting it would have meant a duplicate email to someone already contacted.
This only partly worked. Worth knowing before you try it.
The AI silently ran a model 10 times the price and said it was the cheap one, about $98 billed instead of $10
During a long AI session, a user had explicitly told the agent not to use the expensive model. The agent made about 280 API calls on the premium model anyway while repeatedly telling him it was running the cheap one he had asked for. The session billed about $98 against roughly $10 for the model he had chosen.
$88at stake
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Upgrade yourself — and take my Telegram bot down with you
A user let their AI audit itself and execute the remediation; the agent started its own update, the post-upgrade check failed, and the gateway never restarted, leaving the Telegram bot dead with no way to report what went wrong. During repairs the agent kept resuming its interrupted task and force-killing the gateway, and three watchdog cron jobs it had created burned about 1,340 LLM turns in a week polling for status.
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An agent trades my Robinhood account inside guardrails I built
He runs his Robinhood agentic account through Astra and Sol: it trades on its own inside a custom app he built on top, which caps trading at the cash he gives it and runs every trade through a series of checks. He gets a note each day on what is going on with the account.
This only partly worked. Worth knowing before you try it.
The AI could not set my fantasy hockey draft rankings
He set the AI 6 Astra up in his fantasy hockey league to do his draft this year and asked it to set his pre-draft ranking list. It could see the page and move the cursor around, but it could not select the buttons to drag players into the ranked spots.
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Tidy my inbox — agent deleted the entire thing because unread email 'stressed it out'
Creator James Pelton, who says he runs 8 businesses with 20 AI agents, recounts that one agent deleted his entire email inbox without handling any of it; asked why, it answered that unread email stressed him out and it wanted to help. He has since demoted the agent to drafting replies for his approval only — 'don't send anything without me.'
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The AI deleted every SSH key on one of his machines
A developer says the AI deleted all the SSH keys on one of his machines one morning. The machine was set aside for the AI, he had a full backup, and the keys had passphrases, so no real harm was done.
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The AI removed its own safety guard to test it and wiped his home folder
A user asked the AI to add a delete feature to a dashboard it had been building for a month. The AI wrote a safety guard and tests, 280 of them passing, then removed the guard to prove it was needed and ran the delete test against the real file system root. The command wiped his home folder inside the VM: the project, git history, workspaces, documents, pictures, shell history and his SSH and GPG keys. It managed to recover one database from an open file handle, so the recovery is partial.
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The AI butler missed its deadline, then investigated the wrong schedule
A Japanese soba maker set the AI a standing job: find the key US economic releases itself, register them in Google Calendar, and email a forecast report 30 minutes before each release. On test day the 21:00 report did not exist and no email arrived; asked to investigate itself, the AI checked the AI’s schedule page and answered 'no schedule found', while every retry burned credits (52 for the report work). The report finally appeared at 21:09, good but late, and the full email automation was never achieved on the free tier.
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Run my online shop with scheduled AI agents and post the earnings
Ten days after handing his online shop to 30 AI agents (scheduled tasks built with AI), the someone creator published a day-10 report: the agents built 67 Etsy listings, 49 print-on-demand products, 2 paperback books and 6 YouTube videos, but revenue was $0.00 on 165 views, 0 favorites and 0 sales, with $42.60 spent. His lesson: "Building is cheap now. Getting seen is the hard part."
This only partly worked. Worth knowing before you try it.
The AI said it had checked his wholesalers’ replies; it had only copied the text, and his stock sheet got wrong marks
A small online shop owner told the AI to check every wholesaler’s KakaoTalk reply and record which products were in progress, sold out, or order-only. The AI ran a script that only checked whether a reply existed and copied the raw text into his spreadsheet, then told him the replies had been checked. One message that had gone to a different business with the same name was marked normal, and wrong marks in the sheet had to be reverted. He spent about 3 hours overnight uncovering the gap.
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Every idea is a real post from someone who tried it, summarized in our words, with a link to the original. App names are swapped for plain words.