It's complicated. I grew up in suburbia (Michigan = CARS), went to college in NJ (walked for 4y), lived a couple years in Seattle (public transit), back to Michigan (car), and have been 10y in SF. I learned how to ride a motorcycle when I moved here. I now travel by foot, bicycle, Vespa, SUV, and (rarely) public transit -- I choose my mode based on weather, purpose, or if I have to take my 5yo kid. I suspect those who only cycle have quite a different perspective of life on the streets of SF than those who only walk or those who only drive. I also think it's possible that you can't apply the experience of one city to another.

Regarding the "congestion" in SF: it isn't what you may think. I can make ANY round-trip in SF in a car just as quickly as on my bicycle (though my Vespa wins every transportation contest in SF, hands-down). SF is ~ 7 miles x 7 miles. I live SMACK in the center, and work 2 miles from home. It takes me as little as 10 minutes to scoot (I can lane split in a few spots), 12 minutes to drive, and 14 minutes to cycle one way (if I crank). This city is optimized for car travel, at the expense of cyclists.

As for how cyclists are perceived: Two pedestrians in crosswalks have been killed by cyclists in the past two years in SF (1 and 2), leading to plenty of articles (NYT, Huff, LAtimes) about the sociology of cycling in SF. At least one of these incidents is widely known (article in Bicycle magazine). Just in 2013 alone, four cyclists were killed in SF (usually by trucks). To help people appreciate the attitude towards cyclists here, read THIS.

Maybe my perceptions are "bollocks." Maybe, not.