I'm with Dionysus and Chandler Bing (before Monica converted him into liking baths ).
I usually don't have time to wallow around in my own filth in the tub. And people usually respond, "how dirty do you think you are?" Not very, but I still don't like the idea of sitting in a bathtub, getting all pruney, when I could be lying on my nice new comfy couch after a quick shower.