Just a dash of red in this otherwise very monochromatic photo gives it the pop necessary to grab your attention.

Notice how the same black & white photo doesn’t have the same POP as the color photo.

Fuji X-E2, FUJINON XF 18-55mm, ISO 6400, ƒ/8, 1/320

Red is one of the colors that draw the most attention in a scene. Stop signs are red for this reason, like on this school bus–your eye will see it in a location. Also, this is why the lights are red on the bus. Same as the tail lights of a car. You want them to be red when you hit the brakes so that those following will be alerted.

The lesson is simple when there is just a splash of red in the photo, you will draw your eye to that area of the photograph. If you don’t want that to happen, don’t include it in the image.