Severus Snape: I told Dumbledore you were helping an old friend into the castle. And now, here’s the proof.

Sirius Black: Brilliant, Snape. You’ve put your keen mind to the task and come to the wrong conclusion. Now, if you’ll excuse us, Remus and I have some unfinished business to attend to.

(Snape puts his wand at Sirius’ throat…)

Severus Snape: Give me a reason. I beg you!

Remus Lupin: Severus, don’t be a fool.

Sirius Black: He can’t help it. It’s habit by now.

Remus Lupin: Be quiet.

Sirius Black: Be quiet yourself, Remus!

Severus Snape: You two, quarrelling like an old married couple.

From Harry Potter and the Prisoner of Azkaban (2004) | Produced by Warner Bros.