The closest I came to color regret was when I walked into the showroom after my car was built and saw a Rain Forest Green with Natural Leather interior. That color combination and sleek lines made the nearby Jaguars and Ferraris look awkward - the Masserati however seemed to hold it's own
If I'd seen this color before ordering, I might be driving RFG/NL/BL instead of LB/GG/GG.