I've just returned from a three-week car-free vacation in Berlin. For almost all of my travel in that city, I used a bicycle or walked around. As expected, I didn't really see anything about bicycling in that city that surprised me:
1. The bicycle infrastructure, while haphazard and of varying quality, was everywhere.
2. At any given time, literally tens of thousands of people were underway on bikes (some of them smoked while riding).
3. Very few people used specialized clothing or equipment while riding. They ride in whatever they're wearing, few of them use helmets, and almost none of them use clip-in pedals;
4. Traffic is regulated in such a way that bikes have priority away from major roads: cyclists are allowed to ride in bus lanes, for example, and to ride the opposite way on one-way streets.
5. Bikes and bicycling are not a preoccupation of most riders; many bikes seemed poorly maintained, and the locks that most people use there are not much of a barrier to even the most casual thief.

The things I observed in Berlin probably did little to alter my own car-free life back home in Seattle; I've been car-free for a long time, and Seattle is a pretty friendly place to ride. It did forcibly remind me of some basic assumptions about bicycling as serious transportation, though:

1. A LOT more people would adopt bicycling if there was enough dedicated infrastructure to make it possible to ride everywhere in the entire city without having to resort to vehicular cycling. (I didn't used to believe this, but have gradually come around to this point of view. I often forget how intimidating cars can be to a novice, or to a visitor unfamiliar with the terrain.)
2. More people, especially young people, would ride if not for the false perception that you have to wear special clothing and equipment to ride a bike and survive.
3. Bicycling will never become mainstream in this country if you make a "culture" out of it. (The laughter directed at Portland is not entirely misplaced.) Bicycling is ubiquitous in Berlin, but it's not perceived as special. Few people there think about it at all; like driving a car, it's just something you have to do to get somewhere.

The main thing that I came away with from my stay in Berlin is this: if you want to get a lot of people to ride bikes, you have to spend some money. That extensive infrastructure didn't get there all by itself. It seems like an unreasonable expense to many, but it doesn't have to be Copenhagen-fancy, it's way cheaper than providing car infrastructure for an equal number of users, and when you're done you've markedly improved the quality of life in the city even for people who never even touch a bicycle.