Takeru's not-so-well-kept secret was that he enjoyed watching Kayano get completely flustered over him. Teasing her, making her blush, making her angry was high on his list of all time favorite things to do.

The actual secret part of it was why he enjoyed it so much. Having her focused on him, looking only at him, paying attention only to him, having her world be him for just those few moments pleased him immensely because Takeru was too accustomed to not being important in the eyes of those he cared about the most.

So he'd keep teasing her, because even though she said she loved him, he liked the reassurance of being the most important thing in the world to her—even if for just a moment.