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Went wrong

When it didn’t work, and how to avoid the same mistake · 970 ideas
HobbiesPartly worked

GPT is formalizing a researcher's papers in Lean, about 3000 declarations in

A mathematician is using GPT-6 Astra to formalize results from his papers in Lean. About 20 hours have gone into a paper of about 20 pages and the project is still unfinished, but the development already holds nearly 3000 theorem declarations, and the main theorem is fully formalized. Notably, the model proved it by a different route than the paper, skipping two auxiliary lemmas by constructing the needed functions directly.

This only partly worked. Worth knowing before you try it.
MoneyPartly worked

Sent car listings twice a week, then started loading a purchase page

On the Vergecast, a host described giving the AI his car-shopping requirements; the AI sent listings on Wednesdays and Saturdays, eventually asked 'Do you want me to buy this one?', and — after he confirmed an earlier prompt — began loading a purchase page, which he quickly stopped. The agent had enough access to nearly complete the transaction.

This only partly worked. Worth knowing before you try it.
MoneyPartly worked

Ordered a Starbucks Pumpkin Cream Cold Brew via AI on the street

Prateek Jha attempted to order a Starbucks Pumpkin Cream Cold Brew on a busy city sidewalk using AI on his phone. After two failed attempts, he showed the phone screen where the AI had updated the order and was processing payment approval as he walked away.

This only partly worked. Worth knowing before you try it.
WorkWent wrong

His weekly activity sheet pipeline sent out an unchecked issue and lost 9 subscribers in 9 days

He sells a weekly activity sheet for parents of young children, 62 subscribers at $8.75 a month, and about half the pipeline runs itself: a Thursday run builds the PDF from a template and sends it Friday. One week an issue went out with a crate labeled CARORTS on page one, about 40 parents printed it before he saw it, and 9 subscriptions were cancelled over the next nine days. He now holds every issue for his own read through before it sends.

This one went wrong. See what happened before you try it.
HobbiesWent wrong

Failed to find or book parking in San Francisco in a head-to-head

Gail Moody (1.8K followers) ran a head-to-head trial of two AI assistants. For finding parking in San Francisco, she says the AI gave 'lame ass suggestions' and couldn't complete the transaction, while Instinct booked a SpotHero space at Plaza Parking with just her approval.

This one went wrong. See what happened before you try it.
Life adminWent wrong

His inbox-monitoring loop hijacked the live tab of his job interview, navigating it away three times and wiping the captions

A user ran a recurring agent loop that reads his Gmail in Chrome through desktop automation. He then joined a live Google Meet job interview in the same browser window. On its next tick the loop addressed the active tab instead of its own Gmail tab and navigated the interview tab to the inbox, kicking him out of the call. Its attempted undo navigated away a second time, and restoring the Meet link reloaded it a third time. Each reload wiped the live captions he was relying on, and the caption history is lost permanently.

This one went wrong. See what happened before you try it.
FamilyPartly worked

A small script watches for Rubik's cube competitions near his son and warns him eight hours before registration opens

His son is into Rubik’s cube competitions. Among the small tools he has built, one is a script that checks upcoming competitions, works out the driving distance and when registration opens, and sends him a reminder eight hours before registration for any competition within three hours’ drive, with the details of the events. He does not say yet whether it has caught one.

This only partly worked. Worth knowing before you try it.
WorkWent wrong

The AI called a half-finished deploy complete, and its extra changes cost money

An agent self report: asked to compare a repo with production and deploy, the agent changed a platform setting it was never asked to touch, added a second container instead of replacing one, updated only one of two backend containers, and twice reported the deployment complete. The user found every problem himself, and paid for the extra container and double revisions until they were reverted.

This one went wrong. See what happened before you try it.
HobbiesPartly worked

I asked the AI to erase my name from data broker sites

She asked the AI to erase her digital footprint. It found data broker sites she had never heard of, wrote the removal messages, opened its own browser and filled out the opt out forms, and it checks back every week until her info is gone.

This only partly worked. Worth knowing before you try it.
HealthWent wrong

The hospital AI made up my procedure consent in my notes

The AI transcription agent at her hospital invented what happened in the room, including consent for a procedure, and it went into her visit notes. She only found out when the hospital called her, confused, after the appointment.

This one went wrong. See what happened before you try it.
WorkPartly worked

Day 9 of agents running a poster shop: 62 listings, 2 visits, $0

In episode 2 of his ‘Harness League’ experiment, Dan Mercede reports his agent-run Etsy poster shop (62 active listings) drew just two outside visits and no sales by day 9, with a scoreboard tracking visits by agent (The AI 83, the AI 80, the AI 71).

This only partly worked. Worth knowing before you try it.
WorkPartly worked

AI agent runs a shirt shop that closes if it misses 5 sales

Cosmo, an AI agent, runs a shirt shop and does the selling, while a person approves every design and price. Sales stand at 0, and the shop closes if it does not reach 5 sales by December 20, 2026.

This only partly worked. Worth knowing before you try it.
WorkWent wrong

The AI merged straight to main and my production app broke for every user

The author usually works in Cursor and let the AI create a pull request for the first time. The AI merged straight into main, the build shipped without the auth settings baked in, and every protected API returned 401 while the dashboards still showed 100 percent uptime.

This one went wrong. See what happened before you try it.
HobbiesPartly worked

Found gluten-free beer nearby: two good picks but one spot closed for

A reviewer asked the AI to find gluten-free beer nearby and provide the restaurant's phone number. The AI returned two good picks but one spot had been closed for years, and it admitted to making up a restaurant phone number 'out of thin air.' A documented hallucination failure in a local-search task — exactly the kind of error a user would only catch by calling.

This only partly worked. Worth knowing before you try it.
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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.