Well considering I'm on my third NSX in the last 16 years, I regretted it every time I sold one....although I didn't regret selling them for more than I bought them for every time.
It's why the wifey still lets me keep buying them
I'm seriously considering selling my latest one lately....I don't know why but I've been obsessed with the Cayman GT4 lately
I know I will probably regret it though
Here is my current one....I'll try to dig up some pictures of my other ones.