While it would be great to be able to up and move to wherever in the world you consider to be paradise, immigration law exists for national governments to control who is able to stay in the country permanently and what their legal status is in matters like citizenship. Immigration laws may vary greatly from country to country and may have influence from outside bodies, like the European Union. Additionally, some States have periods of “nationalisation” for residents before they are permitted to become citizens, kind of like try-outs for joining the team.