When Michael asked me if I had a photo of Tony for this post my mind visualized him in B&W. Tony is a colorful man but I see his portrait in B&W.
Some subjects just demand to be B&W and some demand to be color. An obvious subject for color would be a rainbow. Another obvious subject for B&W other then Tony? This question can only be answered by the photographer. It's subjective.
Here is the original photo this came from:
Another reason this just doesn't work is that this photo was taken in very low light—and it's hard to get great color in low light. If color doesn't complement your subject you're better off just to get rid of it. Happy shooting.