All your three stages are quite normal....
1. Confusion. Why am I buying parts and mods for a car I don't have yet. It took me 6 months to finally find a Monaco Blue, manual, cpo, clean title, premium, sport, winter, etc etc and let me tell you... you can accumulate a lot of parts in 6 months
2. Excitement. Picked up the car and started modding on day 1 (that was back in 2008).
3. Joy. Out of 15 hrs awake in a day, I spend at least 3 hrs in the car. There is one word, joy.
Why do you feel remorse?