You should always consider the cost implications. The money has to come from somewhere — it's just that on the NHS, other taxpayers are the ones responsible for your health problems.
(I'm a Brit who's had a little too much social liberalism today. Sorry.)
The NHS is one of the greatest things we've invented in the UK. It's not always perfect but everyone uses it at some point, some more than others that's just the nature of illness. You may not have had to use it yet, but one day you or your family might and if that happens you'll be glad it's there.
I happily pay my taxes, exactly so that someone like Mary can get the required treatment. Hardly any individual can carry the costs of such medical investigations and operations.
Yes, I certainly know how lucky I am to live in a country with a nationalised health service. And I am eternally grateful to the rest of the population who have contributed to my healthcare via their taxes. I know that if I live to be a hundred, the taxes I pay won't get close to covering the cost.
I can only speak for myself, but I'm glad some of my taxes get spent of things like this, even if I were never to benefit, it's still an absolute good.
(I'm a Brit who's had a little too much social liberalism today. Sorry.)