Worst dev experience was when I was asked to "take a look at" a propriatery Windows app built by a now non-existent team at the company.

The code base resembled the quality of legacy code where about every hour I felt like I needed to vomit. But that wasn't even the worst part for me.

This was the first time I had to develop on Windows and was sent a separate dedicated laptop for this. Now I started to have a bad feeling about this because as far as I had known every single dev at the company used company Macs for development (including me for other projects). It turned out the Windows laptop was indeed configured for a non-dev team :)

Having liased with IT admins for a day I finally got my environment set up and hit install on the dependencies and in 10 minutes it got to less than 10%. The laptop was pretty powerful so I couldn't belive wtf was going on, fans were ramping. Checked task manager and the company Anti-Malware was hogging the whole CPU.

I was so mad that I managed to get the IT admins to completely disable it and then it was only the pain of working with shitty code on Windows which would have been more than enough from the start. Thankfully it only lasted a week.