Without opening his eyes, Snape muttered, "I learned that the inanities of students are endless. That Scorpius Malfoy has either been permanently disowned and warned away from the Manor on pain of hexing, or that he's inherited all the usual Malfoy pride and stubbornness, and then some. I learned that he has a hitherto-unsuspected talent for painting squid.
I learned that, when asked for suggestions, the originality of your thought processes ensures that you never disappoint. And I learned that, when your suggestions are argued against, you take the criticism with equanimity, even when it's your friends who are under discussion: quite a pleasing discovery."
He cracked one eye open, just wide enough to see Al through a dark haze of lashes. "And what have you learned?" he murmured, echoing Al's greeting - which Snape had begun to realise was customary - back at him.