I've owned six diesels. I believe it's more macho than anything. What's the point of music if you don't play it. One of our neighbors bought a Harley Sportster about a year ago. He can't ride it enough and when he's home, it sits in the yard with it's engine running a lot. I asked him why as it's getting no air flow across the jugs sitting there running. He said he just likes to hear it idle. At least he was honest. All of my trucks have been my work route trucks as well as TV and family cars. If my starter was so delicate or the engine so tender I had to let it idle extensively, I'd trade it for something else.