A 1980 MGB.

The fuel gauge was only loosely related to the fuel level, I ran out repeatedly before learning to use the odometer instead.
The dashboard switches would sometimes disintegrate, springs fly out, when you flipped them.
The electric radiator fan was controlled by a relay that melted if the fan ran too much, and the engine would overheat. I lived in Arizona at the time.
The brake system totally failed in traffic and I had to stop from 40 MPH using the emergency brake. I think that was the most scared I have ever been in a car.
The supposed catalytic converter was an empty shell (I bought the car used, I did not do this) so once a year I would take it to the mechanic, who would tune it to pass emissions, get it tested, and immediately take it back to the mechanic to make it drivable again. The statute of limitations has run out so I can admit that.
Finally, the water pump failed in an incontinent way when I tried to sell it, the buyer had second thoughts after that and I had to fix it and start over selling.
It was cute, cheap, and drove well, but a creation of Hell.