Harry Potter when...
Everyone in Hogwarts looked forward to your lessons, they found you fun and laid back unlike other teachers. You had sarcastically called Harry sir and he took in seriously unlike the rest of the class who knew you where joking.
"There's no need to call me 'sir', Professor."
"There's no need to call me 'Professor', Harry. But I guess I'm so used to James, Sirius and Remus' sarcasm I'm still trying to come to terms you more like Lily."
"You knew them."
"Of course I do, we went to school together. There some history for you all. Our group was called the Marauders. Prongs, Moony, Padfoot, Wormtail, Evans and y/n/n."