You were the young Charms Professor in Hogwarts of the Marauders, Sirius Black, Remus Lupin, Peter Pettigrew and James Potter of course, they were 16 you were 20, yes, young.

And you were going out at night, when you notice the four in the courtyard, SMOKING! You were shocked right now, how could students smoke here?! God.. you're gonna teach them right now, plus they got their back facing you.