Personal taste preferences aside, what would be your guess if asked to name the most detrimental product on McDonald's Corp.'s (MCD 0.67%) menu in 2015? Recently, we named the best menu item at McDonald's this year from an investor's perspective. In the following presentation, we return to award the prize for the worst item the burger giant offered up to customers over the last twelve months. To learn what this item is and why, simply click through the following slideshow: