Cars are bad for the environment. They also hit people, which hurts in case you were wondering. Why would you want something that hits people and makes breathing tougher existing in the world?
Bikes are easy exercise. Now I'm lazy and I don't like to work out. Power to the people who do like to work out, but I am not one of those people. However, I love to ride my bike. I'm not very well informed about how many calories you burn or how much fat you're going to lose, but it's physical activity and that's all that matters.
You look environmentally friendly riding a bike. You'll inspire people to think about the environment and get brownie points at the same time!
Cars are expensive. If they go out of style, I don't have to buy one and can stick to my bike. So for the love of the good Lord, please help me in my crusade to eradicate cars. I have no money.
Helmets become a little less necessary. Yes we should wear helmets, but I chose not to because I'm an adult and I can make my own decisions. They're ugly and make your hair look weird. Not to mention the fact that they make me feel safe and that takes away from my feeling of adventure. Please don't follow my example. More bikes, less harmful crashes.