These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Spice and Wolf
Alternative Character Interpretation: There is some ambiguity as to the real personality of Nora Arendt. Lawrence believes that she's as naive and innocent as she seems, but Holo claims that this is only a facade.
Audience-Alienating Premise: It's kind of hard to sell a series about medieval economics, which is most likely why the marketing plays up what little Fanservice there is (which also backfired and gave people the wrong impression of the show.)
Best Known for the Fanservice: Just by looking at a Google Image search of the title, one would assume Holo spends half the series naked. She first appears in the nude as a consequence of, well, not having any clothes with her when she goes back to her human form and is naked in the OP, but for the most part remains fully clothed, but fans and even lots of official images and merchandise (and This Very Wiki) would have you believe otherwise.
Growing the Beard: The sixth book in the series (the final arc in the anime) sets off a three-book epic that introduces Lawrence's totally-not-apprentice Cole as a third main character as well as a central driving plot (a church conspiracy involving one of Holo's deceased great-wolf kin's remains)
The "Stupid potato" line from the dub. (In the original Japanese version, she called it an "Evil Potato", which might have been even funnier.)
The nickname "Korbo."
Moe: Holo can act this way to get what she wants from anyone but Lawrence, but she also has some genuine moe moments, either when she's eating an apple, demonstrating her naivete about the day and age, or having a woobiemoment.
The Woobie: Holo when she gets lonely and homesick.
Woolseyism: The translations try to make the dialog appropriate for the medieval-esque European setting by having the characters speak in modern but formal English with few or no contractions. Words that are rare in modern usage but still valid like vexing are used as well. This makes the dub dialog sound suitably old but it avoids the problems caused when pseudo-old English is attempted.