Why is Switzerland not in the Europen Union? Why do they opt out?

There are many reasons for that. I give you he most important reason:

Switzerland has according to its constitution a so called half direct democracy. It's not only the parliament (with its 2 chambers) making the laws of Switzerland. It's also the Swiss people who can vote on practically any subject (there are some exceptions though but this is not significant here) are even able to overrule a decision of the parliament. More or less any legislative act can be overruled by a referendum (50000 signatures within 60 days after the legislative act --> referendum). In the EU, the European Court plays an essential role and this court can overrule a legislative act of a country if it doesn't correspond to the European law. That means that a decision of the Swiss people could be overruled by the European Court. This is in contradiction to our system. First of all, Swiss people can't accept that their decision (particularly one with a referendum) could be overruled. Secondly, Swiss people have a tradition that they don't accept the decisions of 'foreign' judges. There is one exception to the latter. The decisions of the European Court of Human Rights (which of course is not an institution of the EU).

Because they have a damn site more common sense than us Brits!

Because they have Swiss army knifes and dont need the union.

Agree with Caggy.

The remain out so they can charge anyone visiting Switzerland a 30 euro fee in car tax. Nice little earner.

Actually, they applied for membership in 1992, but there were two negative referenda (on the EEA in 1992, and on the start of accession negotiations in 2001) that put that application on ice.

Nevertheless, in 2004 the Swiss Parliament decided to maintain the application for membership, while the European Union maintains its position that the EU stays open for Switzerland to join.

So they can stay indepenant and keep bank for both sides come world war three.

No european country on its own could start a world war, but a massive pact (like the EU) could.

So Europeans can have a tax haven. Nobody has to be in the EU.

I've lived in Switzerland. I once had a Swiss girlfriend. Don't get me started. We are better off without them.

Because they have more sense than we have, as my fellow first answerer highlighted here ...