This evening I finished Horimiya The Missing Pieces. As a series which is created from a collection of incidents from the manga that didn't make it into the anime series it was more a collection of stand-alone episodes rather than a continuous narrative, although some of the episodes were connected.
I'm sure that The Missing Pieces will be appreciated more by those who have read the manga than those, like me, who haven't. However, I have to say that I found some the episodes to be just a touch on the dull side and even a bit too silly, but having said that I thought is it was a good series and I enjoyed watching it.