I went to the US once and brought back a bunch of chocolate bars like Snickers, Twix and KitKat, which we also have in Europe, because I was curious how they compared.

The difference was night and day. The US ones tasted like pure sugar encased in wax, where in the European version, the chocolate was much nicer and you could actually taste the ingredients, and not just sugar. Though I also find them too sweet for me.