I have been subbing for the organist in our ward for the past few weeks, something I always enjoy doing. Our ward chorister has a habit of choosing some of the more obscure hymns, which also tend to be the ones that are more difficult to play. Today, I put up the hymn numbers on the little board and looked over the hymns before beginning to play prelude. Listed as the opening hymn was #11 'Twas Witnessed in the Morning Sky, a hymn I have never heard before. As I started playing it, I realized that not many people were singing. I attributed this to people not knowing the hymn, like me, and I preceded to pump up the volume to compensate for the lack of singing.
After the hymn was over, the conducting member of the bishopric stood up and apologized to the congregation for the hymn, which he said was actually hymn #12. It was only after I looked back up to my music that I realized that I had played the wrong hymn! I had no idea, and I wouldn't have known if he hadn't said anything. Hymn #11 is "What Was Witnessed in the Heavens?". Oops!