I am French and have lived in several countries:
Spain for 3 years, absolutely loved it and plan on moving back there in the next year or so.
The US (Florida), liked it enough but was sick of not being able to walk to most places and being scared of getting sick and having to fork off huge amounts of money for medical bills. Loved how multicultural it was and how easily I could speak different languages.
Italy, the place was gorgeous and I loved the language and the culture/food but food people, especially men in Rome quite rude and it was hard to feel at home there.
Australia, gorgeous landscape very nice people, easy enough to make friends as lots of expat but extremely expensive and so far away from everything and the time difference makes you feel quite isolated. I also loved the wildlife as much as I hated it, bugs there are 3x the size of an insect in Europe and I would be a bit paranoid about spiders and and venomous jellyfish/sharks.
The Carribean, very nice people and gorgeous landscapes, but extremely conservative and quite boring in the long run. I wouldn't live there again as I was really bothered by the gap between the poor and the rich and didn't feel I could have the same quality of life as I would in Europe. Would go back on holidays though.
I now live in Germany and considering and I love Berlin, winters are rough but Berlin has this vibe that you can't really find anywhere else. My biggest challenge living in Germany is learning German. It's extremely tough and people usually speak English anyway so it's easy to be lazy and switch to English. Germans can also be very set in their ways and come across as a bit cold/formal which is odd when you've been living in warmer countries for a while (not too bad when you are French though). Still getting over shaking people's hand instead of giving them kisses on the cheeks. 