A global government is sold as something that will increase convenience. One currency, no trade restrictions, no borders, and no wars sound great, but no one mentions the downsides.

A world government would mean you couldn't escape from shitskins, draconian laws, and high taxes. A global government would mean that you would lose your culture and language. You wouldn't be able to vote or your vote would be outweighed by a dominant culture. A global government would have less freedom, less free speech, and guns would be banned.