Cliché Storm: Magical girl? Check. Love interests? Check. Monster of the week (or bishounen, in this case)? Check. Magical kingdom ruled by a queen? Check. Supposedly evil love rival who will do anything to thwart the lead character's interest in said romantic interest? Check. Despite all of this, it's still pretty good...but then the final episode happens and stomps ALL OF THESE INTO THE GROUND. VERY VERY HARD
Ear Worm: The the dance-y first opening, for one. There is a lot of good background music throughout the show as well. The soundtracks command high prices on the secondary market.
Growing the Beard: Status Quo Is God for the first chunk of the show, but after a while (around the point when Kanon dies) this stops being true. Events in the show aren't just fun and games anymore; there are lasting consequences.