Because Britain always only cares about its own interests and is selfish, just like Brexit now. Although Britain's energy is great, it is always unstable, so it has become a troublemaker in Europe and even in the world.

historically, Britain has always wanted to be independent from European countries. Therefore, although Britain is a European country, it has always thought that it is independent from Europe. Therefore, in the affairs of European countries, Britain has always played a very disgraceful country. In general, Britain will create troubles because of its own interests regardless of the interests of other countries. For example, the current Brexit, when the European Union was established, Britain thought that the EU was weak and unwilling to join. When the European Union was running smoothly, Britain forced its way in. Now that the EU is operating normally, Britain feels that it has suffered.

Britain's policy of "balance of power on the mainland" has made Britain a dung beetle in Europe, but without this dung beetle, Europe will not smoothly realize the integration process. Because there are cultural differences among countries on the European continent, and there are still some grievances. Even if reunification is forced, various contradictions will break out. Therefore, although Europe looks very United to the outside world, it is only the appearance of strange bedfellows, because all European countries have suffered from the world war, so they are willing to develop peacefully.

For European affairs, Britain has always been a balanced strategy of ignoring and balancing its opponents. Within the EU, it is always a silent person. However, Cameron still made a historic mistake and put the referendum on Brexit into practice. So far, Britain has been trapped in social division and political chaos, and its international status and influence have been reduced.