Kid at the bike shop: "....Dude, do you eat an Oreo just before you sit down in the dentist chair?"
Me: "No, why?"
Kid at the bike shop: "Then don't drop your bike off at the shop covered with mud"
That was the conversation I remember years ago when I first got into mountain biking. It has stuck with me over the years and I struggle with it every time I go into a shop.
Is it better to drop off your bike with some dirt on it so the guys know you actually ride it. Or is it better to clean it up out of respect for the wrench?