See, stuff like this is what Reddit is good for:
Fast food workers of Reddit, what is the one menu option at your employment that you would recommend people never eat?: AskReddit
For some reason I feel vindicated that one of things on the list is ice. I never get ice in the soft drinks, partly because I don't generally like my drinks super cold (unless there's a climate-change induce heat wave going on), and partly because ice just takes up space that could be used for more beverage. But now there is another reason: apparently those ice machines aren't easy to keep clean and mold free. Ewww.