Most of my cars were in Europe. I am not going to talk about Zastava (Yugo) except it has some nostalgic memories, but were absolute POS.
Of major companies, worst by far were Opel (GM). I had Opel Ascona C, that was first Opel model that had QC from GM. It was so terrible that rear spring once detached from body due to rust. Engine was for that model year (1988) pure gem, 2.0 8V OHC. Opel still had great engines (not diesels though), but rest was just horrific.
As someone said "never say never again," I got Opel Vectra B which supposed to play in the same league as Passat B5 on European market, except VW left behind Opel in dust with that model. It was cheaply built, so appliance looking that it was horrific. Gearing in that 2.0 16V engine that has roots in Cosworth was so bad that maximum speed of 215km/h could be achieved in like 20 miles as 5th gear was super long. Generally it was OK reliability wise, but everything else was just cheap, outdated etc.
Had Alfa Romeo, Lancia, never had issues, unlike many others. They were real deal to drive, although Lancia due to transverse 5cyl diesel was bit heavy in front.
Had numerous BMW's, never had major issues, except X5 35d that had 1st gen. SCR, but that is not confined to BMW as it is problem across industry. Had numerous VW's, including infamous PD 1.9 and only once had to change flywheel. Had Peugeot's, Renaults, and except they drive bit too soft for me, they were OK. Peugeot 2.2hdi GT was real diesel rocket.
Another POS is Toyota Land Cruiser. Got LC Prado that is sold here as GX470, with 3.0 D-4D engine 4cyl diesel engine. Engine is great for such vehicle performance wise. Reliability wise, I could run factory of EGR valves. However, that is nothing compared to POS suspension and brakes. Constantly replacing control arms, rotors that can make top 10k km before vibrating. Solved issue with brakes by using EBC rotors, but suspension is ongoing saga. I got a car to access some mountain parts that have dirt roads which turn into mud etc. from September to May. Sometimes I am afraid I will stay stranded due to suspension issues. Usually after brief excursion of asphalt, something needs to be changed. Absolute bottomless money pit. Since I am driving it like 3-4000k km a year when I visit family, it is not worth of selling it and buying something else.