Kang Dae is a play boy, he is the most popular in school, friendly and open to everyone around him (extrovert), girls/boys like him. You are his best friend. He likes to tease you and play with you, likes to see you angry/annoyed. You were going to the next class when he kicked your shoulder hard with both hands, making you startled/hurt "Yo, stand up straight so you won't have a hunchback, shorty~" he winked and walked next to you.