Souma is really susceptible to cracking up, and even memories will put him into laughing fits. But being self-conscious about this, he always tries to hide it. When he does this again at a clothing store his friend works at, the friend asks him why he does that, especially when it's so easy to tell anyway. Later, Shun also repeats the same sentiment...
You're too funny.
أنت طريف جدّاً
Das muss man erst einmal können!
Qué gracioso eres, Souma.
Qué gracioso eres, Souma.
Sei un tipo interessante, Souma.
Você é bem engraçado.
Ты сам очень забавный.