IDK it isn't bad if done right. I went with a red, blue, and black theme with my current build and it looks good. I got my ram set to pulse and my RX480 blinks in sequence. My Spec Alpha case sets the tone nicely with the red fans and sharp angles.
My 11yo son and his friends said it looks like a computer from the movies and that got me thinking. Yeah they might be right. If you've ever watched Star Trek or Star Wars or any sci-fi really they aren't using boring black or beige boxes. The computers in the movies have blinking buttons and neon lights flashing everywhere.
So yeah I got a computer like the ones in the movies and I think that's pretty cool.