I had to smirk at some of those things. Light fixtures were hit-and-miss, in the 1970s-80s. My ex bought a VW Fox, new. Three months later, one taillight housing was filled to back-bulb level with water. I really had to work on that, with aquarium sealer and to be sure, put a couple of pinholes in the bottom of the housing. That would drain into the trunk, but better there than into the light housing.
Starters, yup, a lot of eurotrash cars had that problem. Remember, Fiat was kicked out of the American market in 1979. Nobody wanted one. Europeans were okay with them, because Europeans, living in an area about as big as Ohio/Pennsylvania/New York, could easily take a train anywhere. Or a friggin' taxicab.
Owning a car in Europe was, and probably still is, a status point, first. Bragging rights. Fiats look pretty sitting there, parked.
Parts were a problem. When you bought one, you were dependent on an inept, self-important braggart. Malcolm Bricklin. Two years into the Yugo project, he was already bored - he was letting the company self-destruct.
Valve springs...yeah, the engine, again. Fiat engines were and are crap. The Fiat 500, returned when they bought bankrupt Chrysler, showed they had learned nothing in 30 years' absence. Now, Chryslers and Jeeps, having been designed mostly by Fiat people, often in Europe, are just as crappy.
All this could have been worked out with development work. Yugo, Zastava, was just a motor-car works, run by the Party. No engineering. No new-product development. No customer-service reps.
The sad part is, it was sold to exactly the kind of people who couldn't deal with such problems - the marginal, the broke, the people with no Plan B or emergency money. Yeah, such people would have been better off with used cars from established brands.
I expected trouble when I bought mine - I got more than I thought (clutch failure, and then the engine destroyed with a timing-belt failure) but I knew it would give me a lot. The little things, like wiring problems (those WERE little things in that era) I could deal with.
It was a learning experience - both mechanical and political. I learned why government-ownership of industry, in a planned-economy environment, like Yugoslavia, does not work. It was the beginning of my conversion to Free-Market Conservatism.
So, in that regard, I'd say, probably, my Yugo was worth the price of admission.