My hatred for cars developed in 3 stages. The first involved a casual observation that well, they seem to cause a lot of death don't they? Both directly through traffic fatalities and indirectly through urban pollution, global warming, sedentary lifestyle issues, etc.

The 2nd stage occurred when I visited Phoenix AZ for the first time. It's a major city built from the ground up to serve the automobile. You basically can't do anything without a car. You can't walk to the corner store. It's miles away. There is no sense of community anywhere. You can be in perfect health and yet feel handicapped because walking won't get you anywhere. And last but not least, even with a car city like this, Phoenix is still plagued by traffic jams! It's just so depressing.

The 3rd stage set in when I bought my first e-bike. It didn't outright replace the car, but it did replace around 90% of the trips I had been making by car. It cost a tiny fraction to buy it and maintain it, and it made me angry to think of how much of my personal wealth had been sunk into automobiles and fuel over the years.

Regarding stage 2, the first documentary I watched that really drove it home for me was The Human Scale. It's a little dated at this point, but still relevant in the central points it makes about urban sprawl.