As winter plods along, you may wish you could just hibernate until spring. But there is, indeed, joy to be found in the quieter months of the year. While the trend may have come and gone in the U.S., the art of hygge, that feeling of being ultra-cozy and content, is just part of everyday life in Denmark. The thing is, the Danes know how to thrive in winter. You might already know they're the happiest...