i just enjoy working on my car, and getting it set up just right by myself with simple tools and some ingenuity makes for an awesome saturday in my opinion.
when i was a kid my dad taught me to be a fearless tinkerer - he promised me that as long as i paid close attention when taking something apart, i would always be able to put it back together again. he was taking apart the toaster on the kitchen table (on a newspaper, of course) to fix the auto-up mechanism and he showed me how to group fasteners by function, recognize wear marks on mating parts and put sub-assemblies into separate piles. i was probably 6 at the time. i asked him where he learned how to fix a toaster - he smiled and said it was the first time he'd ever seen the inside of one. i tore apart every toy, old clock, broken camera, etc. that i could get my hands on just to try and see if i could put them back together again. probably a pretty common story w/a lot of folks on this site i imagine.
it's a huge point of pride/satisfaction to be able to work on and improve a simple mechanical device - for me, anyway. that's why i have a 38 yr old car. sure, it's cool to look at and fun to drive, but truth is i get just as much joy out of fixing and modifying it. and i know my dad would be proud of me for stringing the front end the way he taught me when i was in high school.