I constantly see cases where people have spent money on crown molding, and then painted the ceiling, walls, and molding all white. That’s a great idea for making the crown molding disappear!
It’s much better to give the wall some color, and then to also paint the ceiling. At least paint the ceiling a shade or two lighter than the walls, but better yet, give it a “sky” look. Here’s an example of a home office in the Scripps Ranch area of San Diego:
In this case, we not only “popped” the crown molding, but by adding indirect LED lighting inside the top one on a dimmer switch, we can change the mood of the office from dawn to daytime to evening. Our artist painted a sky in the soffit that looks like San Diego; gray-blue with some wispy fog.
But even without a soffit, and just with colored ceiling and walls, you will really get your money’s worth out of your investment in crown molding.