Mud: Why do dogs love it?

I would have thought dogs like to mess with or roll in mud because the minerals/chemicals in the dirt helps them fight skin parasites and/or itches which may have been caused by things like allergies to shampoo, carpet or other floor chemicals or food to name a few. That's why some domestic and most wild animals do this, elephants for example. Some dogs eat particular types of grass that they identify by smell - why? because these help them kill intestinal worms. All these behaviors may not have anything to do with breed difference, but life style instead.