Yeah, it's partially that I've (so far) had exceptional luck with my vehicles! In my 15 years of driving I've only had maybe 10 parts changed. I did the easiest myself--an alternator, a couple of serpentine belts, etc. I sometimes change my own oil.
Sometimes I don't know enough to diagnose a problem, though, and I take it to my buddy. He usually does the fix and I watch and help a little, but I don't know enough about the whole engine and how it all works together, at this point.
I want to buy a car to take apart and reassemble, but I don't currently have a space I can do that in. Though it just occurred to me I could get a storage unit, probably.