There are subjectives, and then there are these. While you may believe a work fits here, and you might be right, people tend to have rather vocal, differing opinions about this subject. Please keep these off of the work's page.
Examples (more-or-less in alphabetical order by name of LPer):
DrunkGoomba's LP of Ace Combat 4. The quality is awful and does not improve over the course of the videos; his gameplay is mediocre, often pulling rookie mistakes and falling for basic enemy tricks, and subsequently complaining about them much to the chagrin of the viewer; his commentary is awful and irrelevant, often rambling about utterly pointless topics in his high pitched voice, which after a while becomes extremely grating and painful to listen to. There are few complete Let's Plays for this game, and this clearly isn't one of the good ones.
EvaXephon is one of the most infamous LPers. His Livestream of playing games are generally terrible (he dies so many times that it isn't funny), and his tales are often worth a few laughs...
He's been getting banned from every stream site because he pirated and streamed Red Dead Redemption before its release. Everyone who hated him, and the people he banned who kept trying to tell him to stop streaming it, reported him to Rockstar.
He streams games before release date... like Just Cause 2, where he played the pirated game and dies on every single attempt to kill one of the bosses.
Imperial Terra is another hated Livestreamer, when he wants someone to watch his stream. He spams his thread with images that are generally not work safe, rather than just letting it run its course. Although on average, video game streams on 4chan are normally frowned upon due to the amount of spam that the topic creator makes to garner attention.
iJustine's Let's Play of Portal 2. She gets stuck on the easiest puzzle of the game for eight minutes! The worst part is that this is after the puzzle that demonstrates the way portals work to you. iJustine got sick of everyone telling it like it is (e.g. "This Sucks"), and set the whole Let's Play to private. However, you can watch a tolerable version here and it's still available (all parts) on Viddler starting here.
The staggering idiocy is brought into full view in this video. On the right: iJustine. On the left: the video author's 12 year old sister who has no knowledge of the Portal series and little gaming experience in general (certainly less than iJustine claims to have). Watch and be amazed.
Not to mention that she manages to ignore most of the plot while playing it. There may as well have been none. She even ignored the famous "Lemons rant," one of the funniest parts in the entire game! To paraphrase a quote of hers: "Who's Caroline? I thought I was Caroline."
At no point does she refer to any of the characters by name, calling Wheatley "Mr. Eyeball" and GLaDOS "the potato". This is extra insulting since she has the subtitles on-screen telling you the character names!
It only gets worse. Whenever she does refer to something by its proper name, she "corrects" herself and says the made-up name. She basically has a party in the middle of one video and they all end up talking over the aforementioned lemon rant, and given her lack of reaction to the rest of the dialogue, it probably made no difference.
The now long-gone early works of Linkrulezall. Blatant Hypercam 2 watermarks that sometimes cover important details (made even worse by his frequent references to said important details), single-digit framerates, audio that was way too quiet (to the point where the game audio was downright inaudible, and you could barely hear his commentary), and banal commentary that consisted mostly of Link being a Captain Obvious. Topping all that off, he had a habit of failing to finish many of the Let's Plays he started (the only one he finished was his WarioWare, Inc. LP). To be fair, he has gotten better.
The ultimate lowlight was when he made a "Boss Guide" of Super Noah's Ark 3D, when he only uploaded one part, and it was plagued by all the same problems mentioned above, but with a framerate of about 1 FRAME PER 3-5 SECONDS!
MasterknightDH's LPs are severely flawed. His speech is difficult to interpret since he suffers from extreme Elmuh Fudd Syndwome (think PsychedelicEyeball slurring), and his commentary tends to be either banal or whiny about his perceived 'game balance' issues. That alone is terrible, but he also has a colossal ego; he can't take even the slightest criticism or insult, and usually ends up shutting off comments or ratings. He's also infamous for his rant videos, where he demonizes anyone who disagrees with him (at one point even saying that the girls who live in his area deserve to be RAPEDbecause they mock himand dislike him).
MaxiMaxi10 has 1,551 videos, half of which are him just doing random crap around the house. His Let's Play videos are where we get into the majority of this entry. He does camcorder LPs where his camcorder's at a bad angle and you see the right third of the screen. His commentary's boring, and you often find yourself watching the action figures on top of his shelf to see if they'll be more interesting. Even worse, whenever he's criticized, he pulls a Christian Chandler and blames all his faults on autism.
Quadraxis14's early LPs of Contra III and Kaizo Mario World. Contra III was filmed on an awful camcorder, and features an inexperienced Quadraxis stumbling over commentary and making really awful jokes. Kaizo Mario World was recorded competently, but he constantly reloads save states (causing his emulator's save state screen to flash on the screen constantly) and still hasn't gotten humor down. Retsupurae riffed on several of his videos, and ended up admitting in his God Hand LP that he's greatly improved. For his part, Quadraxis found the riffs hilarious.
Queenie Z. Whether it's her severe Girl-on-the-Internet syndrome, her unfunny commentary, her constant use of outdated memes, or her shrill voice (with retainer sucking to boot), you'll share the RPer's pain.
Retsupurae has covered the first two parts of her Eternal Darkness: Sanity's Requiem LP. If you check the videos out, you'll notice that Part 2 has over 30,000 fewer views than Part 1. For added irony, the video description of the former says "You're watching Part 2? Didn't Part 1 scare you off?"
She's gotten somewhat better over the years; while it's unlikely she'll ever live down the aforementioned LP, she has apologized for it and considers it something of an Old Shame. However, YouTube account was closed some time ago. It wasn't Retsupurae's riff on her LP of Eternal Darkness at all, or the hatedom she earned from said LP, that drove her to close her account; according to Queenie Z herself, it was due to copyright infringement for using clips from Elfen Lied and the Tales of Symphonia OVA in some of her videos.
SuperCrazyHealthBar is a famously awful LPer. Despite his excellent picture quality, many of his videos suffer from severe audio clipping and his commentary is abysmal, consisting mostly of him rambling aimlessly about things that don't have anything to do with the game, occasionally dipping into a weird demonic growl and shouting at the screen. He's so terrible that Retsupurae believes him to be a troll, although it's never been very clear.
The now-closed YouTube channel teddybearmassacure. His video quality and skill was subjectively decent, but everything else was abysmal. Many of his videos had loud noises in the background and obnoxious co-commentators that sounded like ten-year-olds. His commentary, meanwhile, was irritatingly banal, with "jokes" consisting of Seltzerburg-style pop-culture references and stale memes. He would've probably been small-time if Retsupurae hadn't dredged out one of his older videos. His improvement over the years before he closed his channel was minimal at best.
The entire play through of Resident Evil 3: Nemesis by YoVideogames is extremely painful to watch. The player winds up overlooking or plain forgetting about certain key items several times, forcing him to backtrack just as many times and leads to time being wasted because the player didn't bother to edit it out. The player also winds up trying to be fancy with conserving ammo by attempting to avoid as many enemies as he could, which leads him to blindly running into zombies and other monsters and takes unnecessary damage because of it, which also leads to a ton of deaths that could have been avoided and it also leads to the player redoing sections of the game over again without editing it out. The lack of edits to save the viewer's time is very infuriating and gets even worse when you see that the player DID attempt to speed up (literally) the process of the viewer catching up a few times but then just forgets about it for the rest of the LP. On top of that, because the player never bothered to read the instructions (game manual and in game manual), which leads to moments where he ignores explosive hazards that he could have used to kill zombies in one blow and how to combine gunpowder for different effects and saving inventory space. The puzzle sequences aren't any better as the viewer is forced to watch the player bumble about in solving them for over 5 minutes. While the player tries to excuse his bad playing style on lack of play time on the game for several years, it goes out the window when he declares the game to be bad at the end of the LP and blames it on all the screw ups he had to endure.
Similarly, the Let's Play of The Legend of Zelda: Ocarina of Time has Max piloting the control for most of times. Since Max tends to stop playing the game for weeks or months he tends to forget even basic moves, not to mention it took him literally weeks to learn how to use the lock-on and block properly, watching him fighting Lizalfos and Stalfos is particularly aggravating. Max also tends to unnecessarily complicate almost everything and screw up even simple puzzles. Wasn't for Matt helping him at almost all times (in the beginning he refused any help and tips at all) a Rage Quit was almost certain to happen.