One little known feature of HTML5 is Scoped CSS. It's an attribute for style blocks that may change the way we tackle certain styling challenges in the future.
One bizarre trend emerging in this new RWD era is desktop-browsing web designers resizing their browsers to watch the break-points change the layout. The average user never sits at their desk repetitively shrinking and expanding the browser window like a mad scientist. Yup, we're all strange.