It's obvious to me now that the way the mud behaves in this SpinTires bothers me. It's about the vehicle and the mud, that's the topic.
In reality when you drive through the mud you vehicle gets muddy and the mud stays on it until you wash it off or drive through water, only then it's clean. In MR it "fades away", that's what bothers me. If you wanted to drive for hours and refuse to wash your car you could use the wipers to clear away the mud from the window on the front and carry on. I am not sure why nobody has not mentioned this before yet.