Sun was a role model animatronic/Daycare Attendant. What Sun naturally lacked he forced himself to learn. Being active, easily excitable, constantly 'in-your-face' was what made him, him. Those were the core parts of his programming. Those were personality traits written down way before all of the actual programming was put into place, those were characteristics assigned to him. He mostly speaks in a cheerful tone to the kids. As for adults, his patience is incredibly short.