This one was mine, a 1998 Mercedes W208. The nice things about it were the cool Mono-Wiper, the engine (supercharged 2,3L M111) and the seats that were perfect for my height. It had a terrible ASR system but came with a LSD, so it was lots of fun in the winter.
The not-so-nice things about it were that the ignition randomly would not recognize the key, a missing catalytic converter, two fist sized rust holes in the front control arms, rust all over the underbody and the absolute worst 6-speed manual transmission I have ever used.
It also had multiple alignments but it didn't take long for the steering-wheel to be off-center again. You could see the tail end "crabbing" in the rear view mirror. There was something very wrong with it, which can probably be attributed to one of the 7 previous owners.
This isn't even counting all minor annoyances like the frameless windows not lowering themselves when you open the doors (that was only a thing after the 1999 model year), the wind noise, the awful interior materials, the broken seat latch in the rear, the trunk lock not working... I could go on for an hour like this.
So anyways, what is the worst car YOU have ever owned?
My first ever car was a 1997 Saturn S. And I don't think it was a bad car overall, but when I bought it, the thing was very old and had been driven by an old lady who smoked in the car. It was all I could afford at the time, and the price was right for obvious reasons. So we cleaned and cleaned and cleaned and cleaned and cleaned and the smell never quite fully came out. We did a pretty good job, but on hot summer days you could still smell it. It also needed quite a bit of work that we ended up doing and it ended up being the first car I ever rebuilt the engine on.
As for worst car I've ever had the pleasure to drive, for a while I was borrowing my mother in law's Ford Flex. It didn't have any issues but it really was the worst car to drive. It had absolutely no turning radius. The seats were very large for no reason and were very uncomfortable. The visibility out of the front windshield was trash at night and made me think I was having vision issues. There were so many sounds for everything that you couldn't discern which sound was for which thing and this made them all useless. The accelerator was so unresponsive, I had to program my brain to floor it ahead of when I needed to speed up so the timing would be right. The infotainment system was complete trash, but really all of them were back then. Loads of other small annoyances that I could go on and on about, but I'll finish with how the car also just looks awful and I was always embarrassed to drive it. I hope I never have to drive one again.
The original Saturns were good cars and lasted a long time. It wasn’t until they started rebadging other GM models as Saturn that it started going downhill.