My mother's family NEVER goes grey. My Mamaw died at 82 with long jet black hair. My dad's family is generally grey by 30. I'm 41 and have 3 or 4 grey hairs by my part. They don't show much because my hair is some weird multi-color reddish-brown, blondish mess. If I get a big grey spot, I'll probably color. If it sprinkles in nicely, I'll leave it alone.
As for color disasters..........Sun-In. My sophomore year I decided to go blonde with Sun-In. No one told me that peroxide type stuff turns reddish hair ORANGE. Day-glow, vibrating ORANGE!