I heard he was a jerk in his personal life.

I think a world without countries or religion would be really boring. I can also envision a fascist world without countries or religion. Consider this, during the "Enlightenment" when European countries decided to bestow citizenship to the Jews who had been living within their territories for hundreds of years it was conditional upon the Jews giving up everything that made them look different from everyone else. Yes, a world without religion or countries.

Giving Lennon the benefit because I know nothing authoritatively about his live, I would venture to guess that when he speaks of a world without religion or countries he's really talking about a world full of tolerance for other countries and religions.

Countries and religion often seem to me to do more harm than good.  We forget that spirituality is not dependant on religion or public spirited citizenship on patriotism.  I'd gladly say goodbye to both along with the Taliban, the Inquisition, Ethnic Cleansing,war, oppression, and prejudice and I don't think I'd miss such things or be bored without them.  The caveat, as pointed out below, is the specter of a fascist world government destroying what little individuality our current institutions leave us. Still it's a direction worth at least a few moderate steps.