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.
Ackmena (Bea Arthur), even more so since Arthur's death. And it doesn't just apply to fans; people who work on the Star Wars franchise loved her so much that they added her to the expanded universe, wherein she's stated to have gone on to join a group dedicated to freeing Tatooine slaves. She even has a page on the wiki!
Fanon Discontinuity: If there's one thing all fans and creators of Star Wars can agree on, it's that this thing never fucking happened. The only reason it wasn't straight up Canon Discontinuity in the first place is because of the policy Star Wars has on canon; as long as it's officially made and doesn't contradict the films or previous material than it's canon. One of the positives of Disney's decision on the post-original trilogy Expanded Universe is that this monstrosity was finally wiped off the slate.
Hilarious in Hindsight: One of the few things that isn't hilarious anyway — Itchy's "Holographic Wow" features a "proton pack". Clearly, bustin' isn't the only thing that makes Itchy feel good.
The Imperial Guard in Saun Dann's shop looks a lot like Lord Helmet.
The whole special is memetic in how awful it is. George Lucas's seething hatred of it is also rather memetic.
Misblamed: Some fans blame George Lucas for the quality of this, but in reality he had very little involvement due to filming The Empire Strikes Back at the time. In fact, Lucas had one of his trusted former USC classmates installed as the initial director in order to make sure that the special would be at least somewhat faithful to the original film. Unfortunately, CBS proceeded to fire Lucas' favored director and replace him with the guy that would go on to produce Pee-Wee's Playhouse. The results speak for themselves.
According to writer Bruce Vilanch, however, the idea of the special focusing on Chewie's family, and not including subtitles, was all on Lucas.
Mondegreen: Jefferson Starship would really like to knoooooooooow if you'll light this guy on fire.
Narm: The whole thing, but special mention must be given to the actor cameos and the attempt at "warmhearted" holiday cheer at the end: Han, Luke, C-3P0 and Chewie are supposed to be moved by Leia's song of hope, but look stoned/bored out of their minds. Considering that Carrie Fisher was whacked off her skull on drugs while making this special, they probably were.
One-Scene Wonder: While the premise was as silly as the rest of it, Bea Arthur's performance as the cantina owner is actually a bit moving. Sadly, it doesn't save the rest of the thing's horribleness.
Same can be said about the animated segment - looking at you, Boba Fett.
Padding: One theory is that the special was originally to be one hour, but the network wanted to sell more advertising, so they insisted that it be expanded to two hours. That would explain some of the more ludicrous scenes.
Squick: Elderly Wookiee Itchy looks like he's masturbating to holographic alien porn, which is completely wrong and disgusting no matter how far away your galaxy is. He's also watching it in the middle of his living room, in front of his daughter-in-law and grandson. Worse yet, this is apparently a common enough occurrence that they don't even bother commenting on it.
Even worse... this is exactly how the writers and producer wanted it to come across as. Merry Christmas, children! And they would have made it more explicit if not for one of the few necessary instances of Executive Meddling.
They Wasted a Perfectly Good Character: Ackmena, Bea Arthur's character, is actually considered to be the most interesting character created for the special. However, she doesn't appear for very long.
Took the Bad Film Seriously: Bea Arthur, alone among all the big-name guest stars. To her credit, she's talented enough to elevate her sequence into something watchable and almost poignant. She was also no stranger to 1970s variety shows, so she knew how to adapt her Deadpan Snarker Mode to the role. Her own comment on the special years later was that she hadn't been keeping up with Star Wars and its massive cultural impact at the time, thinking of the gig as just singing a musical number to "a bunch of people with funny heads."
The Woobie: Krelman, Harvey Korman's character in the cantina scene. Yes, he's a bit weird with his head hole, but he's so sincere and so lonely, he evokes sympathy almost accidentally. Cantina barmaid Ackmena and her customers as a whole also fit the bill.