yeah. Don't get too caught up with the thin DOF from this lens, and concentrate solely on that. Quite addictive, I have to admit, especially if you're an upgrader from PnS/Prosumer.
You need to have a distinct subject, and then the background must be totally blurred out, or distinct enough to make out what it is, yet not sharp enough to be distracting.
Example: Portrait of a construction worker. Subject is sharp, and in the background you can still make out a crane or something. This gives the photo some context. Like it's telling a story.
Or else a totally uniform and blur background. e.g. the styles you see in macro photography. Insect sharp, and a blur of green behind.