The differences between one country and the next are so numerous that it would be difficult to list them all. The language, the culture, the customs and traditions, the weather, the roads - the whole everything is different from one country to the next.
In fact, so different are countries from each other it's sometimes surprising to see familiar things such as Coca-Cola signs and other logos while abroad.
While on holiday there's obviously statistically a small chance that you'll need the sevices of health professionals, but of course there's the obligation to purchase heath insurance before travelling. If you're living abroad it's a different situation since you're there long term - and will probably have to use health services at some point, even if it's for a check up rather than an emergency.
Even just within Europe, standards of healthcare can vary a lot - and the cost can vary a lot too. This is why international heath insurance is a must if you're living abroad - allowing peace of mind while you get on with all the other things that are different from home.
For a great overview of the differences between UK and Australian healthcare, check out this Guardian article - for a country so close to ours in terms of shared hsitory and language - the differences in healthcare are still marked.