I'm with Xiggi on this one. I shower at Flying Pilots. If I've got a dollar bill or loose change, I will leave it. What I would really like to do at Flying Pilots is leave a tip for the person that takes care of the car fuel islands. If the paper towel dispenser was correctly reloaded (or even loaded), the windshield wash water stuff had less soap and more windshield washer stuff, and there was a somewhat decent squeegee/scrubber thing, I would tip handsomely!
My change cup runeth over because it ain't ever going to happen. At least not in my life time.