No doubt you live in London or a large city.
If you live in Wales as I do, a car is needed to widen your job prospects?
Also without a car I wouldn't be able to just pop and see my friends who live an hour away, it would turn into a farce of having to catch a 40 minute bus into town which is only a 15 minute drive, and then a 40 minute train ride. And then I'd have to make my way from the train station to wherever they lived.
Not worth it. And say if I fancied a walk in the country, or to go somewhere a bit different I couldn't do it with public transport.
I know public transport is more environmentally friendly, but some places afford use of public transport much more than others. Not driving would really limit me.