Ear Worm: Pipiru piru piru pipiru pi! Not only is this repeated in the theme song, it is chanted in a high, squeaky voice every time Dokuro is required to resurrect Sakura, who dies more than Kenny ever did.
What an Idiot: When Sakura gets an opportunity to get rid of Dokuro forever and have his normal school life back where he's not tormented by his classmates or skewered by a mentally unstable angel presents itself, one would think he'd absolutely jump at the chance to take it. Hell, he even lampshades several of the cruel and unfair injustices she did to him that causes her to cry (though to be honest, not a single viewer felt any sympathy towards her) and believe she's not wanted. Unfortunately, Sakura doesn't want her to leave and basically says that he doesn't mind all of the abuse as long as she's with him. It isn't a stretch to say that no one in their right mind would have chosen to do what he did.