WataMote: No Matter How I Look At It, It's You Guys' Fault I'm Not Popular! OVA

Aomatsu is just an ordinary otaku leading an uneventful life in middle school. In an attempt to spice things up, he decides to visit the roof of the school, and it is there that he sees a mysterious young maiden with pitch-black hair. Unbeknownst to him, her name is Tomoko Kuroki, and she is infamous for her bizarre behavior. The conversation that ensues from the meeting leaves a lasting impression on Aomatsu, compelling him to return day after day just to see Tomoko again. Tomoko's view of their meetings, however, is quite different from that of Aomatsu, leading to the two having significantly different memories of a particular event. Source MyAnimeList