The OP was asking for concrete examples in the form of policy decisions. This is one of the only answers so far that comes near that. Health-care is a good example. In Europe, everyone has universal health-care, period.
However, differences between individual states do apply. I’d suggest California is more liberal than some European states. There are states in Europe where the death-penalty still exists, even if its almost never used. I guess you’ll have to look for extremes.
One very clear policy example though, is taxes. Overall taxes in the U.S. are estimated at about 25%. The Netherlands, one of the lesser taxed countries (though we have that to thank partly to efficiency rather than a policy choice that provides our citizens with less social support, for instance), has a tax rate of 38%. Many European countries are above 40%.
Another good example, I suppose, is education. In general, every European has access to higher education, money or no. There is always an easily affordable loan available with generous terms, and many also get additional funding they don’t have to pay back. How much is a gift and how much is a loan is sometimes dependent on how much money parents make. The systems can vary wildly though. In Sweden, you get a fairly generous loan, but pay back a small percentage of your wages the rest of your life. In the Netherlands, you pay back a certain amount linked to the height of your income, but limited to 15 years, and a part of your loan is scrapped if you get your degree, for instance.
But never forget that the differences between countries in Europe are at least as big as differences between states in the U.S., something which Europeans also often forget. The Netherlands is like the California of Europe, maybe more extremely so in some respects. For instance, we have:
- legalised euthanasia
- legalised prostitution
- legalised gay marriage
- semi-legalised drugs
- legalised medicinal use of marijuana
- the highest fuel prices of Europe (yay!)
- no death-penalty
- social security for all
Especially the first 5 are not at all common in other European countries.
On the other hand, we also have
- privatised most national industries (phone companies, cable companies, mail, trains, etc.)
- privatised some parts of social security (such as health-care insurance)
We continuously strive to find the perfect balance between market factors and government control, to curb our costs to be able to compete on international market. Some countries, on the other hand, still face that challenge, such as Germany and France, to a large extent still do.
Also worth mentioning is that the U.K. provides generally much lower levels of ‘socialism’ to its citizens than the average country. For instance, the level of service offered by the NHS is lower, which is, even if the NHS is wildly ineffective at times, reflected in its cost, which is still well below most other European countries (Germany’s being one of the most expensive, but also one of the best).
So while Europe and the U.S. are both nations that shouldn’t be too easily compared, due to the large individual differences of its member states, there are definitely concrete examples that justify the position questioned by the OP.