Other brands of cars
It is fun learning the idiosyncrasies of a particular model of car whatever it may be. You learn to appreciate the design characteristic of the engineers when we own them and work on them. When you think about how automobiles are manufactured it is usually skewed toward ease of assembly. More so today than yesterday. A new Camry almost falls together these days. Reminds me of the old "snap-together" model cars. I'm working on a 65 Corvette right now. The Corvette is rather challenging to work on.
Build numbers and variations are super interesting to me. I just acquired a 65 Impala. Number one sold model of car ever. Over a million were sold. The SS model came with a 3/8 fuel line, even if it had a six cylinder, but you could not get a bench seat. LOL