Another thread inspired me to ask this question: What does the clothing worn by a bicycle operator say about him or her, and does this vary based on locality?
Many people may be able to honestly say that they don't care what other people think about them, but in reality many of us are concerned about the superficial first impressions we make upon others to some extent. Each sub-culture creates norms for dress at work, church, night life, etc. Operational issues associated with bicycling create many incentives to trade these clothes for others that function better for cycling. In some cases, such as at a social function, a compromise away from traditional clothing makes the cyclist conspicuous. In other cases, such as when joining a long distance cycling activity, cycling-specific clothing is the norm and the casually dressed cyclist might feel like the outcast.
So here is a thesis for you all to knock down: The social message made by the clothing worn by a bicycle operator is defined by the prevailing local circumstances under which people cycle.
In a compact city with scarce parking, where cycling is more convenient than motoring and walking for many trips, and many trips are only about a mile, cycling in casual, non-cycling-specific clothing will be the cultural norm and cycling-specific clothing will stick out as unusual.
In a spread out suburban area where cycling is inconvenient compared to motoring, and most people of means operate automobiles, cycling in casual, non-cycling-specific clothing will invite assumptions of lack of economic or legal ability to drive a car, or conspicuous aversion to motoring. Cycling in cycling-specific clothing will invite assumptions of participation in cycling for the purpose of exercise or enjoyment rather than compulsion.
Between these extremes are localities where bicycling is somewhat convenient or enjoyable, and there is is a continuum of casual clothing available that functions fairly well for short to medium distance cycling. Think of riding in Seattle while wearing clothes from REI. Where in the spectrum the cyclist finds himself depends on both the local cycling culture and the local culture in general.
I propose that the way the local culture views cycling clothing is based on conditions on the ground, including land use and street patterns, and on local cultural attitudes about nonconformity, outdoor activity, and environmentalism. I do not believe that the cyclist can change the culture's view of cycling by changing what he or she wears; rather, the cyclist should wear whatever works best for his or her cycling needs, and it is purely the act of cycling that has the potential to influence the culture.