Harry Hart: Manners maketh man. Do you know what that means? Then let me teach you a lesson.
Harry Hart: There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self.
Harry Hart: Are we going to stand around here all day, or are we going to fight?
Harry Hart: I'm a Catholic whore, currently enjoying congress out of wedlock with my black Jewish boyfriend who works at a military abortion clinic. So hail Satan, and have a lovely afternoon, madam.
Princess Tilde: If you save the world, we can do it in the asshole.
Harry Hart: The suit is the modern gentleman's armour.
Merlin: You are about to embark on the most dangerous job interview in the world.
Harry Hart: Boys, I've had a rather emotional day, so whatever your beef with Eggsy is, and I'm sure it's well founded, I'd appreciate it if you could just leave us in peace.
Big Goon: This whisky is amazing, you will shit.
Answer: Details aren't given, but it seems that Dean is involved in local crime along with the gang that hangs around with him. Even if Harry is bluffing, and doesn't have specific proof, it is clear that he is abusive and he has the recording of him threatening Eggsy.