The majority of humans are trichomats i.e. we have three different types of cells in our eyes, each sensitive to a different colour. I already knew about colour blind humans, i.e. dicrhomats. About 1/20 of males are colour blind.
I wanted to end this with a video of interesting mantis shrimp courtship, as extremes in nature, like the peacocks' tail, are often due to sexual selection, and lead to fascinating displays, even if you are not a female of the species in question. Unfortunately I could not find something fitting, so you will have to use your imagination!