I like funky old Eurpean cars, specifically italian cars, Alfa-Romeo. However, as noted below, I tend to obsess about such things and in the process I learned a lot about how other folk make cars. I wrote this as a sort of distillation of what I found.
Each carmaker on the planet has a different philosophy about How a Car Should Be Put Together. Let's take a single case...
Let us say there is a single hypothetical panel in a hypothetical car. It covers something, I imagine it acts as a side panel of a center console. As a baseline, a totally unbiased (and therefore, Martian) engineer examines this cover and determines that it should be held in place with five phillips-head (crosshead) screws.
JAPAN: The japanese would hold it down with exactly five (5) screws. Boring, reliable, soulless, exactly what is needed.
UNITED STATES: For a long time, a US car's panel would be held on with three screws. This has changed, and now not only does it have five screws, all floor workers must have a communal decision as to how many screws it needs, and have the ability to stop the line entirely should a single screw be a funny color.
GREAT BRITIAN: As with the US, previously this car's panel would be held on with three screws. Additionally, these screws would be flat-head style and made of Britishinium Metal, a mysterious alloy that can rust sitting under six inches of oil. Nowadays all the car companies have been sold to the US or Germany, so see those entries.
FRANCE: Only Americans would be so obnoxious as to think how a panel is held on is important. Unions and employee pride are of far more concern. Please come with us to strike for ten more weeks paid vacation and a 25 hour work week.
GERMANY: Every panel on every car is held on with precisely ten aircraft-grade titanium/tungsten alloy nuts, lock washers, and bolts torqued to precisely 15.402 Newton-Meters. Replacements are sold only in sets of 20, and typically cost $350US. A German mechanic will explain to you, in graphic detail, exactly what would happen should you use a "lower quality" nut, washer, or bolt.
RUSSIA: Owing to parts shortages, each panel is welded in place. A cutter costs 8,000,000,000,000,000 rubles (about $12.15 US), and the official wait is approximately 28 months. However, a stranger named "Igor" will sell you a cutter right away for $40 US (cash only). You notice PROPERTY OF SOVIET ARMY scratched out on the side.
ITALY (Goes Fast approach): The Italian is somewhat different. If the panel has something to do with making the car Go Fast, it will be just like Germany's entry, with the addition that every bolt head will have a beautiful logo cast into it.
ITALY (Everything Else): The Italian panel has no screws at all. Rather, it is held in with a very clever arrangement of grommets, snap rings, and C-clips so that it seems to be Part of the Car. However, due to lack of testing, the rubber in the grommets rots in a few years, and since the panel can only be removed with special tool 001.2399943.011034418.104.22.168, the rubber is hardly ever replaced and so tends to rattle. Enthusiasts of this car (all 18 of them) will have endless debates on the value of this panel, some will remove it, some will maintain it religiously, and at least one author will write a book telling you how to make a tool that will work out of a '73 GMC lug wrench.
SWEDEN: The panel in a Swedish car is held on with 25 rustproofed phillips-head screws with lock washers. Curiously, one has to put the car in reverse in order to remove it.