The sound of exhaust can be compared to various types of alcohol. Most cars fall into the 'beer' range. Its popular and consumed in huge volumes, but minimal difference across the board. Performance cars are like wines. Tons of varieties from every region of the world, each with its own distinctive flavour, and all with a bit more kick. After market exhausts are like spirits. Ricer fart cans are like vodka, mostly consumed by kids who don't know any better. V8 muscle cars are like whiskey, the choice of manly men. But the obnoxious Harleys? Moonshine. Somewhere, nobody is sure where, but somewhere it crossed the line from being 'more is better' to 'MOAR BECAUSE MOAR!!!1!!!'. Not surprisingly, there is a big overlap in our mental image of a moonshiner and a biker:
For all we know, those two are the same guy