Explain this passage

[Carol]

No: HPFGUIDX 180668

Tiffany wrote:
> 
> That sounds a lot like Snape & sometimes I think he lost his brain in 
> the Bermuda Triangle also.  I don't hate Snape, I actually have some 
> respect for what he's capable of, but at times he doesn't seem to have 
> all his ducks in row.  I liked some of his ideas & decisions in the 
> books, but his truly grand moments of genius are few & far between, if 
> you ask me.
>
Carol responds:

Oh, I don't know. He managed to convince Harry that he was extremely
brave and worthy of naming his second son after, along with Albus DD.
(Sirius also rates only a middle name.)

Of course, our reactions to any character, perhaps especially Snape,
are partly subjective, but even his mistakes (revealing the Prophecy
to Voldemort) have important consequences, and, certainly, had it not
been for his request to LV to spare Lily, she would not have had the
opportunity to offer herself in Harry's place. She would simply have
been murdered like James and there would have been no chosen one.
Also, of course, he saved Harry's life in SS/PS and gave him the
crucial bit of information in DH without which he wouldn't have
sacrificed himself and the outcome of the conflict with Voldemort,
including the weakening of Voldemort's magic, would have been very
different.

All of which amounts to Snape's being a key player in the plot rather
than having moments of grand genius, I admit. However, Snape does have
some grand moments on-page (showing up Lockhart in CoS, "Spinner's
End," the duel with Harry at the end of HBP, tricking Voldemort with
his Occlumency in "The Dark Lord Rising" (since we later see, with
Gregorovitch, just how strong and invasive LV's Legilimency is, that's
quite a feat), and producing those memories out of his head without a
wand as he's dying--I don't know of anyone who can match that last bit
of spectacular magic.

Much of what Snape does, of course, is off-page, but we don't know of
anyone else, including Slughorn, who can improve on potions as
published in a standard textbook. Nor do we know of anyone else
(unless Hermione's jinxed parchment counts) who actually invents
spells, not just jinxes and hexes and one Dark curse, but
countercurses and at least one charm, Muffliato. He supposedly knew
more curses (surely, schoolboy hexes and jinxes) when he was eleven
than most seventh-years. He's a superb Occlumens, a reasonably skilled
Legilimens, and an expert in nonverbal curses, with fast reflexes, as
several scenes show. And he made two curtains of fire, one black and
one purple, with separate antidotes (you can't drink the purple
antidote and walk through the black fire or vice versa) in SS/PS and,
though it's clear only from an exchange with Lockhart, he made the
Mandrake Restorative Potion administered by Madam Pomfrey to the
Petrified students (and ghost) in CoS. He's one of the few people who
can make Wolfbane Potion, for which Lupin managed to be properly
grateful until he thought that Severus had murdered Dumbledore. His
Veritaserum plays a crucial role in GoF. He is both brave enough and
intelligent enough, not to mention skilled enough, to outwit Voldemort
and earn Dumbledore's trust (to the extent that DD trusts anyone).
Dumbledore relies on him to deliver the Sword of Gryffindor to Harry
in the right circumstances (retrieving it requires need and valor),
and Snape's plan involving the Doe Patronus is his own ("Don't worry,
Dumbledore. I have a plan.") And no one, not even Harry, has such a
bright, beautiful, powerful Patronus. No wonder Snape shows no fear of
Dementors.

Carol, noting that both Harry and Ron regarded the Half-Blood Prince
as a genius (too bad he couldn't have been their contemporary and
their friend)