Money - a lot of people are not aware of the money a car costs over a period of time.
Dependency - you are only able to drive a car in a special time of your life. If you are too young or too old you are not allowed - or it is very dangerous - to be the driver of a car.
There are places you are just able to go by car. This is a problem: they are just made for car people. For instance: malls outside a city. Nobody is shopping in the inner citys, while everybody have to take the car to the mall. This system needs a lot of good working roads, parking spaces and other infrastructure.
Health - in regards of physical activity or is a lot healthier to live in an area where you are able to take public transport. Due to the last mile, which you are probably going by bike or by feet, you get your daily "workout". Also you are emitting much less emissions into the air. It seems that particulate matter of the reason for a lot of illnesses of our time.
Public Space - you are consuming much less public space than people who are owning a car. Parking lots are in habitats of humans all around. They cost a lot of money, are sealing good soil and the precious space in city is wasted to it. There are such nice projects all around the world, where former parking spaces or streets where changed to spaces for everyone.