I frowned, recoiled, and muttered an audible "ew." Thus was my reaction upon viewing this color. We all have our own tastes, but it seems that there's one color most of us can agree is especially disgusting, but that helps it serve a useful purpose.
We talk a lot about color toning, and the truth is, it's one of those subtler steps that can really make a good image a standout image. Sometimes though, it smacks you in the face, as is the case with the color opaque couché, Pantone 448 C. Australian researchers believe it's the "ugliest" color as judged by the reactions study participants had to it, which included such labels as "sewage-tinted" and "death." The research was done for an important reason, however, as the Australian government will now use it on packaging to help deter consumers from buying tobacco products. It's a great example of how things we take for granted as consumers can influence us and how we as photographers can use that influence to our advantage.
By the way, if you'd like to try using it yourself, fire up Photoshop, and enter the RGB triplet (74,65,42) into the color selector. Use at your own risk.
Edit: It seems the YouTube video isn't available in some countries, so here's opaque couché in all its glory:
Lead image by Flickr user Ian Ransley, used under Creative Commons.