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.
The first opening. A more understated example of this trope, but it still counts.
Ear Worm: "Ringo Hiyori", the ending theme of the anime.
Everybody Remembers the Stripper: 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 (see Fanservice below), but fans and even lots of official images and merchandise (and This Very Wiki) would have you believe otherwise.
Fan Nickname: Due to certain similarities in appearance and character, Eve from the second season is commonly referred to as Sheik.
"Korbo" for Holo, due to how her name looks like in her sloppy handwriting.
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.
Memetic Mutation: I Watch It For The Economics started as a meme from the anime also there is the slightly less prevalent but still worth while "Stupid Potato" line from the dub.
In the original Japanese version, she called it an "Evil Potato", which might have been even funnier.
If you go bankrupt, you'll get your head shaved, your teeth plucked out, and then you'll be sold into slavery for the rest of your life. When you finally die, you'll be buried in an unmarked grave. Said "rest of your life" will be 2-3 years at most, unless you're really lucky. Orunlucky. Economics is Serious Business, indeed.
Literally, in the manga, where Lawrence's imagining of what would happen if Holo were to be turned over to the church shows her crying out in agony as she is burned at the stake.
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.