DUI is just one of, but it seems to be the most prevalent assumption people have. It really boils down to the idea that non-cyclists look upon transportation cycling as a hardship. They have to find a reason to excuse this strange behavior. A DUI is a handy excuse, the others follow; exercise, environment, economics, etc. etc. You either are a spandex hamster out socializing, suffering some hardship, or making a sacrifice. The non cycling public sees no other motivation for riding a bike. Fun is a word never spoken in these conversations.

Marc