If you've come to love the UK (despite problems with certain aspects like immigration), then it'd be awesome to become one of its citizens. You'd be British, and the difference between you and people who were born with citizenship is that this was the home you chose, and not the one that chance chose for you. Plus, you earned the right to be British, even with the current system.
Plus all the voting, moving to other parts of the EU, and lack of having to deal with immigration stuff that everyone else mentioned.