BoJack Horseman Christmas Special: Sabrina's Christmas Wish (2014)
To be fair, it was difficult to get a read on the series from just the Christmas special, which - based on episode descriptions on Wikipedia - seems to be extremely different from the rest of the show. This one almost entirely consisted of two characters watching a Christmas episode of BoJack's old show. Given the premise is that the sitcom in question was abysmal, you can probably guess how that went.
The frame story just focused on BoJack and his roommate at Christmas. BoJack's depressed, his roommate eats giant candy canes, and... that's about all you get until the end, when BoJack suddenly realizes the importance of spending the holiday with someone.
Heart warming, I know.
The sitcom episode concerns the three orphans that BoJack's character has adopted experiencing their first Christmas. The plot concerns the youngest of the three, Sabrina, taking BoJack's claim that Santa can bring her anything literally and asking him to bring her parents back to life for Christmas.
The vast majority of jokes were mocking the conventions of 80's and 90's television: the annoying neighbor, dumb catch-phrases, contrived plots, obvious jokes... you get the idea. Imagine watching an episode of Full House while someone sits beside you and says, "This sucks," every minute and a half, and you've got a pretty good idea what this special was like.
There were a few jokes that succeeded in delivering mild amusement, but they were very few and very far between. Ultimately, this is one to avoid.
I suppose I should reiterate that this is the only episode I've seen, so I can't guarantee it wasn't brilliantly playing off of established concepts and characters from earlier. A lot of people love this series.
But out of context, this felt much longer than its actual half-hour run time. If you're not a fan of the show, find something else to stream.