Not having the yukata set on all my characters. (A couple were made after the summer event.)
Never beating Ifrit hard-mode
Not completing all GC quests. (Was on Living On a Prayer at the end of it)
Not completing all the Gridania main story missions
Not getting the "Been There, Done That" achievement. (And stuff involving exploring is usually the FIRST thing I work on!)
Getting a bunch of recordings of Thanalan pre-apocalyptic Dalamud weather and putting them together with the song Hope playing.