excel as an relational database

That reminds me of a story. I used to do IT consulting, years ago. One client was running their 5 person real estate office off a low quality, consumer grade, box store HP desktop repurposed as a server. All collaboration was through their U drive, plus every profile had their desktop folder redirected there.

The complaint was the classic "everything is slow", which turned out to be "opening my spreadsheet takes 10 minutes then it's slow". Yeah, because that poor little "server" had a single 100 Mb jack and the owner had a 1.5 GB excel spreadsheet project where he was trying to build a relational database and property valuation tool. Six fucking heavily cross referenced tabs, some with thousands of entries. He was so proud when I asked him to explain what was going on there. He fired me when I couldn't fix his issue without massive changes to either his excel abomination or hardware.