The front ball joints needed replacing when I bought it.
The air conditioning has never worked (nor have I fixed it).
The hood struts had to be replaced when I bought it.
Since then (in the past 5 years) :
The alternator has been replaced twice.
The heater core has been replaced twice.
The radiator and water pump have been replaced.
The passenger power window mechanism broke and had to be replaced.
There seems to be a problem with the electrical system, as the power windows are often slow, and in the winter when the window wipers, defogger fan and rear defogger are on, the battery indicator goes into the yellow zone.
The cassette player broke.
The heat & vents control panel had to be replaced.
The fuel line rusted and had to be replaced.
The trunk release doesn't work anymore, likely due to rust.
The trunk leaks.
Lately it has been stalling a lot, at stoplights. Occasionally it stalls out when I am driving, which is somewhat disconcerting.
Even with all its problems, I still like this car. The seats are very comfortable and the interior is plush and roomy.
The car itself has a classy look, with nice chrome accents.
The paint has held up well, and has only recently started getting rust.
It feels like a solid heavy car, which gives me a feeling of security when driving. The new cars that I have rented seem like cheap, toy cars, full of plastic.
This is my first car and even with the mechanical problems, I will miss it when I have to buy a new one.
It sounds like you bought a lemon (mechanically), but I'm glad that you are able to look beyond that and still see the car's good points. When you decide to get rid of it, you should check around for a buyer. There are enough Olds enthusiasts in this world that someone would be sure to buy it.