I can hardly remember the days when I had "a favorite color." Nowdays, I've got colors for different things. Overall, silver, which is a shiny gray. Really like the Chevy Hunter Green for cars. Shirts, a deep blue (likely like those crystals). Things like that.
When I can pick colors for Mecha in games (Warframe, Armored Core, etc.) I like going for a black velvet color scheme. Black, white, and an eerie light green (glow in the dark green).
Really want to get to the point where I can get my white mustang painted with a design with a titanium oxide paint, which glows in the dark. During the day, looks normal, but as it gets dark could have gotten flames or hibiscus flowers or something show up.