system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens when a country like the UK leaves the EU?

And why do they want to leave the EU?
gpt
Some British would like to leave the EU because they believe their decision's frame is getting narrower, as the EU takes decisions with all the 28 countries without focusing on one. Plus, they feel they shouldn't be paying loans for other countries.

Now, no country has left the EU, ever. It's hard to tell what would happen. The UK is a special case, since its currency isn't the euro nor is it a country receiving EU's development loans. On top of mind, the UK and the EU would have to sign some treaties: free exchange, the future of the Schengen Zone, etc. The aftermath would be hard for both of them, the UK having to renegotiate commerce treaties with countries, since the previous ones were made by the whole EU. The EU would need to renegotiate the payments of each country to fulfil the hole left by the UK.