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: A Charlie Brown Christmas
Adaptation Displacement: Well, maybe not entirely, but mention the name "Charlie Brown" to many people today and it's a good bet that this special, rather than the strip itself, is the first thing they'll think of.
First Installment Wins: This special still reigns as the most popular Peanuts special of all time, to the point some aren't aware how many there are outside this.
Memetic Mutation: In the dance sequence, see that kid in the orange shirt with spiky hair in front of Linus? That's "5". Given that he wasn't very notable even in the comics, most people know him just for that dance he's doing. You know the one.
Taken mainstream when the cast of Scrubs made a Gag Dub of the special.
Misaimed Marketing: In the original broadcast, there were ads for Coca-Cola in opening and closing credits - in a show that protests the commercialization of Christmas.
Narm Charm: Some of the children providing the voices were too young to understand their lines, resulting in the classic awkward delivery that later became a staple of all Peanuts specials.
Similarly, the awful animation, a direct result of an abysmal budget. The sponsors offered to have it spruced up when it became a hit, but Schulz turned them down, saying it was fine as-is.
Not So Crazy Anymore: The joke about Sally asking Santa for "tens and twenties" has dated rather poorly due to inflation. Granted, that's still a rather lot of money to give to a child Sally's age, but you need to imagine that she's asking for hundreds to translate the sheer excess to the present day.
The Woobie: Charlie Brown as always, but also his tree. No wonder he chooses that one.
A 2005 tribute album to the special and its music includes a new song, written by David Benoit and sung by Vanessa Williams, called "Just LikeMe." It's basically Charlie Brown's thoughts when he picks up the tree, except set to sad music. And honestly, the lyrics are ridiculously depressing.
Hello little tree... Kinda looks like me, Standing all alone, Sorta like it's been disowned...