Some songs can really put a smile on our faces. We're talking about feel-good, upbeat tunes that just sound happy. But sometimes, catchy major-key melodies hide something more sinister.

"This upbeat shift happened during the great depression ... After a couple of years decline, poptimism is back. The 20 best-selling songs so far this year score 57% on the happiness scale.

Exercise and upbeat music are inseparable. When you go to the gym for a workout, you often hear upbeat and fast-paced music ...