The best (and worst) summer hits of the past decade

Songs of the summer — you know them, you love them, and according to some, they're an entire musical genre that is in danger of melting away like sweet sugar syrup on a popsicle. 
It is true that it used to be a lot easier to judge which mega hit dominated the airwaves during the heatwaves. How do we measure the success of a single that you can't escape during the summer months now? Billboard charts? Spotify streams? Music video hits? Inspired memes? 
We're taking a look back at