When I think about it, there seem to be three main reasons. First, to travel abroad. This is why most people leave the country. The percentage of Koreans traveling abroad is increasing, so it will be like a lot of people leaving Korea. Second, to practice what people have dreamed of or to find and try new things. This is the case for studying abroad, immigration, and employment abroad. You can also leave to do all the activities you've dreamed of, or you can leave because you want a new mind and a mental state. Finally, you may have been hurt by someone or something that made you feel like you couldn't live n your own country or wanted to leave. However, this is not a common case, nor is it the case for many people. It's not a common case, but for example, you can get betrayed by someone and get hurt and leave because you hate your country.