Sasami-san@Ganbaranai S01 E01 I'll Start Trying Tomorrow

Sasami is a hikikomori, who stays at home all day watching her onii-chan interact with others through her computer. On Valentine’s Day, after Sasami gives Kamiomi some chocolate, he unwittingly gives it to Yagami Tama, not knowing the meaning behind Valentine’s. After Tsurugi informs him about the tradition, Kamiomi finds himself wishing for chocolate from Sasami, and inadvertently turns the entire world into chocolate using his power as a god.