What's the worst thing you've seen Excel used for?

A Google Sheet used as a password manager that every employee had access to. To keep it “secure” the cells with the passwords were hidden by changing the background color to match the text color.

Someone posted this last year... It still blows my mind.

In two different companies I've seen people refer to "the database" when they actually mean a spreadsheet. That's not just a terminology mixup, these things were super complex, with pseudo-relational tables, lookups, links to other files etc. The sort of thing that should be in an actual database, that has less chance of breaking in obscure ways when someone inserts a row or types a value over a formula. It was actually pretty impressive, in an "impending doom at any moment" kind of way.

Also had one where there was a spreadsheet of everyone in the business top to bottom, shared by HR and IT. Both groups needed a list of staff, so why not just keep one, right? This thing had personal details like home address and medical conditions, plus things like salary (inc garnishments), performance management notes etc, as well as of course their username and password (which was assigned to them and they couldn't change) and security questions and answers. It didn't even have a password on the file. I noped tf out of that place as quickly as I could, but for reasons even worse than that stupid spreadsheet.

I remember a story my dad told me about a guy at his work who didn't really know how to use Excel, and so had dragged the cell and column spacing out in order to have one huge cell, in which he typed all of his calculations - which he did manually with a calculator before typing them all longhand into his giant cell 😁

Company schedule entirely written in Google Sheets. When I originally took the position over, the owner wouldn’t settle for an alternative solution.

The previous IT person worked there previously for about 10 years and had been compulsively adding features with AppScript the entire time. It was auto sending emails, handling inventory, maintaining project files, you name it. I briefly looked at how it worked and there were easily a dozen script files, a few of which were thousands of lines.

I was able to replicate most of the important parts of the system that he wanted to replicate in about two weeks in between other work with one script file and something like 50 lines.

I eventually left for reasons unrelated to the place and only ever had to fix issues once every 6 months or so, which I consider pretty decent for an unattended Google Sheet shared by 5 users.

I’ve since returned and rebuilt the schedule a second time with a proper database and the whole thing run 10x smoother and more reliably.

Company-internal service where the users would write their desired configuration into an Excel file. Then they push that into a Git repo, which triggers a deployment of the service with the configuration read from all the Excel files.

Someone once commented about a regional ISP with a customer base about five figures in size. Did they use a database system to track customer billing? Nope. All the customers and their billing info are on one spreadsheet. Billing customers means manually crawling through the spreadsheet and typing up the bill.

i was unfortunately responsible for this one...

we developed a wireless communication protocol which was specified in an excel sheet, and it fell on us devs to implement the message types specified in the sheet. however since the specification kept changing we had to constantly update the message types in our tests to make sure they conformed. so i said "fuck it" and built a program that allowed me to "import" an excel file in a python program, which exposed all messages as classes that could be instantiated with automatic unit conversions. just drop the excel file of the day in the right place and run the test suite.

anyway that's how the excel sheet became the formal API definition

To send images for graphic design.

A CRM for a large client. A VERY large client.

Gantt Chart

My company uses excel for costing proposals (not crazy). In order to accurately cost, they decided to include everyone's salaries. I was all for it because the transparency helps keep everyone fairly compensated, but some were less enthused. Sadly gone now.

An oil company which had an MS access DB and a form configured for it with no checks for formatting that would insert the fields of the form directly into the database, and then if they wanted to make a change, they would export the entire database as csv, open it in excel, make changes and use that to overwrite the entire database.

This had been going on since some time in the 1990's. They finally wanted to move to a modernized databasing/operations solution which is what my company does.

I successfully cleaned 75% of that data, however it took 37 regular expressions and a script that was about 800 lines to account for every possible mis-entry, incorrect format, and merging fields if they were empty from newest records to oldest records until the fields were no longer empty where possible (essentially collapsing the records together to get as much data on each unique object which may have had N records over time through the database).

It is UN-BELIEVABLE what actual businesses get away with.

There's the guy who built a roller coaster . https://youtu.be/yYaLQ3LazYM

Not exactly what you’re looking for, but how about a flight simulator?

https://eeggs.com/items/29841.html

Sex tracker... So many empty sheets...

https://www.bbc.com/news/technology-54423988

The tracing of Covid in the UK (specifically England) was collected in .xls files

It started its life as a tool to track the contents of promotional SKU's, but different stakeholders kept adding increasingly complicated logic until it all depended on huge array formulas and VBA, and a recalculation took 1, then 2, then 5, then 15, then 30 minutes on a laptop, at which point we abandoned the whole thing and everyone went back to keeping track of their own piece manually.

A government case management system with thousands of citizens data along with their citizens numbers next to their full address, used for active cases relating to people and their money. This spreadsheet was on the desktop of a coworker and that coworker only.

A works/construction department in a medium-sized town. They had an Excel spreadsheet that had a HUGE number of screens. Anyone wanting to do commercial real-estate construction had to not only fill out these forms, but keep them uptodate and submit the updates at end of each work day.

The thing was HUGE and had lots of interdependent screens, where if you picked an item from a dropdown menu, it unlocked a bunch of other complicated screens or panels, and so forth. Each screen had 30-40 items and fields on it, and there were multiple dozens of screens you had to tab through.

To run it on the jobsite, construction contractors HAD to buy a pen and touchscreen Windows 'tablet' ($$$). The whole thing had been written and maintained by one guy over the course of a few years.

EVERYONE hated it. The guy who had written it wanted to get promoted to management, but nobody else wanted to maintain it so he was stuck.