I always loved the parts where Harry discovered something new about the wizarding world, so how about the first time he sees wizard candy on the Hogwarts Express? I love the fascination Harry has with the new things he discovers.
Sirius:They're both right. Moony is evil and it's your own fault that you got detention. You need more experience. Am I right, Wormtail? Peter:[nods] Lily:[pouting] okay, okay. I'll train on my poker face then.