Why? I don't know where you are coming from, but the world is a big place and there are lots of nice places to go. Granted, there are visa / immigration issues in plenty of countries apart from the US as well, but frankly for decades now the US has been on the decline in every measure of livability: health care, education, incomes, leisure time, commute time, etc, etc. About the only thing the US nominally leads in is a vague notion that you can make more money here than in other countries, but even that is subjective relative to the cost of living and quality of life.