My first car was a black '89 Mustang LX Hatchback with a rip-roaring 2.3-liter 4 banger. It was a gutless wonder with enough empty space in the engine compartment to stand in but with a 5-speed manual it was fun as hell to drive. I eventually got rid of it because it was falling apart.
I didn't see myself ever owning another Mustang after that but fast forward 9 years and I'm fortunate enough to have a father-in-law with a love of old cars. His personal collection is nothing but old-school Chevy's but, knowing that I've always been a Mustang fan, he agreed to help me rebuild one. We looked for a while and found one on eBay that seemed to fit what we were looking for. An early-production '65 coupe with numbers matching 289 and tranny. Upon arrival it looked like a great jumping-off point for a rebuild. Well, as we started in we began finding more and more stuff that needed to be replaced or rebuilt. The pristine pony interior wasn't so pristine. The numbers matching 289 ended up being a 302 out of a '71 pickup. The slightly-dinged fenders ended up being full of rust and body filler.
Through it all, though, I do love working on it and keep on imagining what it will be when it's finished. Unfortunately, I don't get to work on it as often as I'd like. It's 160 miles away in my father-in-law's shop. But eventually I'll have put in enough weekends and it'll be finished.