For Europe, healthcare is for non-residents *relatively* affordable -- if something goes wrong, you'll be out thousands, not hundreds of thousands (as happens to Canadians and Europeans travelling in the U.S. without insurance; they can get billed $50-100K just for treating something like a simple fracture).

The danger is if you need to get medevac'd home, and that applies even if you're in your own country. I have a co-worker who was visiting Hawaii with her elderly mother when the mother suddenly became very ill. They wanted to get her home to California, but she was too sick to sit up on a commercial flight, and a medevac would have cost at least $150-200K. She ended up dying in Hawaii.