Cadence and Shining Armor both feel there's something missing in their relationship. I'm no expert, but I think it might be communication.

The original comic can be found here: http://kitsunehino.deviantart.com/art/What-is-missing-Comic-432715400

Caitbug's Channel: https://www.youtube.com/channel/UCH6dxbc0kfA1Nw3XoMXeBPw