[after catching Harry scribbling on his paper]
Professor Severus Snape: Tell me, what would I get if I added powdered root of asphodel to an infusion of wormwood?
[Harry doesn't answer]
Professor Severus Snape: You don't know? Well, let's try again. Where, Mr. Potter, would you look if I asked you to find me a bezoar?
Harry: I don't know, sir.
Professor Severus Snape: And what is the difference between monkshood and wolfsbane?
Harry: I don't know, sir.
Professor Severus Snape: Pity. Clearly, fame isn't everything, is it, Mr. Potter?