How can people afford cars?

Ok, lets have a look at replicating my day using public transport.

To make it fairer I'll omit giving my girlfriend a lift to work, and stopping to have lunch next to a field because it was sunny.

So- meeting is at 1pm, lets work out how to get there:

07.25 I walk to the bus stop at Friern Road, get on the 63.

At Elephant I get on the Bakerloo line and take that to Paddington.

I then grab a coffee and jump on the train, arriving in Cardiff with one change at Bristol Temple Meads.

It's 11.43 so I can grab some lunch and stroll to the Industrial estate where the client has their office.

Meeting over- it's twenty past two, next train is 14.55, which if I grab a taxi I can make.

This gets me back into Paddington at 17.06 where I retrace my earlier route to East Dulwich.

I've spent £7.20 on a travelcard, £183 on my train ticket, and £9 on the cab from the clients office to Cardiff Central Station.

I left the house at just past seven and got back at half six, for a total cost of £199.20.

In comparison I actually got in the car at twenty past eight, gave my girlfriend a lift to work, and got home at half five, having spent £50.

In my view driving won that match.

Not really. I would spend the time on the train working which, at the cost of my time, would pay back the difference between your £200 and £50 more than once. Plus, you haven't factored in all your car costs, as andyp points out - and add insurance to the list.