The reason why the United Kingdom wants to leave the European Union is pride, but personally, I think that the United Kingdom could have more advantages if Great Britain (especially older people) has less pride in the old great British Empire and the times when they conquered 35.5 million kilometers of land such as easier trade or easier travel around the world.
The United Kingdom would also have a better economy and the British population would have more conveniences.
According to Expatica, the pound has been consistently on the decline since the results of the referendum became clear on 23 June 2016. An initial sharp drop has been followed by several slumps and a persistent overall decline. This leaves the pound sterling to euro exchange rate 15% lower than pre-referendum levels. The pound declined immediately against the US dollar and the Australian dollar, with rates plunging by 17% after the vote. This means that people wanting to exchange pounds into other currencies are getting significantly less. Anyone buying pounds will find the current exchange rates particularly lucrative.
Due to the drop of the British Pound, a fairly large British airline called Thomas Cook was forced to shut down a few months ago, leaving 600,000 travelers stranded all over the world!
In addition, the UK would have one currency that works all over Europe and they wouldn't have to change their money when they travel. The United Kingdom would be more organized and people could live, work, and study in most European countries. Lastly, many people living in Britain would not have to be deported to other countries