livability isn't the same as safety. The USA is very livable but you stand a better than average chance of being shot, caught in tornadoes and ice storms and hurricanes (think New Orleans and Katrina) and earthquakes (San Francisco). Even famine, believe it or not:
http://www.ft.com/cms/s/0/ebc72728-122f-11dd-9 b49-0000779fd2ac.html?nclick_check=1
And if things do go wrong there's no NHS.
As for the other livable countries, they're mostly prone to extremes of heat or cold - apart from Belgium, which may well not exist in 20 years' time, which is hardly safe!
Lovely place to visit, wonderful people. But for safety you're probably best off where you are now.