He was always nice to you when nobody was there, ignored you completely in public.

The schools most popular and attractive bad boy

he bullied your friends and others or fought people but he never even laid a hand on you, in fact he protected you- well..without you knowing..behind your back

now you were in one of the the public showers in hogsmeade trying to clean up your shirt after one of your friends accidentally spilled beer on it, as you were cleaning your shirt someone walks in..