What is the Most Offensive Word You Can Think Of?

The 'N' word, the 'C' word, the 'F' word; all words many consider offensive. Now days we can't turn on the television or log on to Facebook without hearing or seeing words we consider offensive. It also seems that these 'offensive' words are more common place than those that aren't considered offensive. Does that mean we're insensitive as a society? Does that mean those words mean nothing anymore? Regardless of why these words are present, I want to know what word you consider to be the most offensive.