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.
Denny is, supposedly, an intelligent if slightly naive boy about to head off to university but given his actual behaviour - following a couple upstairs and jumping into their bed mid-foreplay, hitting on Johnny's fiance and then telling Johnny, selling drugs when he's the adopted son of a banker - even Wiseau himself admits the film makes more sense if you assume Denny has quite severe socialization and learning difficulties.
The scene in which Mark tells Johnny a story about a woman that was physically assaulted by one of the "many" men she was seeing seems oddly sketchy if you pay close attention to Mark's facial expressions as he tells the story. Mark can clearly be seen slightly smiling after saying "she ended up in a hospital on Guerrero Street". His situation behind the break-up with the "unseen" Betty character also seem to be very suspicious after hearing this story out. Lastly, when Mark tells Lisa to get out of his life following Johnny's suicide he proceeds to hit her in far harder fashion than Johnny is accused of.
Claudette's dialogue makes much more sense if you assume she's a drama queen and an attention whore - traits that clearly run in the family. If, as she claims, "nobody listens" to her, this is probably not the first time she's made up something like breast cancer, hence Lisa's calm reaction.
The Newgrounds flash game gives an extended ending: Johnny is an incorporeal alien sent to Earth to learn earth customs. When he kills himself, he's merely releasing his alien form to return to the mothership and, provided the player collected all the MacGuffins, turns Earth into a giant spoon.
"I Will" is pretty good too, for a cheesy love song.
Pretty much the entire soundtrack is pretty good. It's rumored that this was the only part of the film Wiseau had no control over.
Big Lipped Alligator Moment: Several but first and second prize go to the scene with Mark shaving and the football games respectively. They're so pointless that even Tommy Wiseau and the other actors don't know what the point of those scenes are. And Wiseau's the freaking writer.
Creator's Pet: The movie would like you to believe that "Johnny is a wonderful person" (as the characters constantly remind us) who is unfairly betrayed by his best friend and fiance. To everyone in the audience, though, he's a creepy fellow who doesn't even seem to be human. Yet he's the protagonist of the movie, an obvious Author Avatar, and played by the director himself.
Cult Classic: The Room continues to be screened in L.A. and other cities to this day, thanks to becoming a cult phenomenon. Not really surprising given how fascinatinglybizarre it is. Tommy Wiseau himself comes to these screenings to discuss the making of the film, though he does not reveal much....
Darkness-Induced Audience Apathy: Johnny is a wuss, Lisa is incredibly stupid and callous, Mark is a douchebag, and Denny has drug problems. The writing and acting don't help, either.
Dude, Not Funny!: Tommy laughs after hearing the story of a cheating woman getting beat up to the point that she had to go to the hospital.
Ensemble Dark Horse: Both "Doggie" - the dog that is lovingly referred to as such by Johnny at the flower shop, and Chris R. seem to be considered the only good actors in the film, but that is not really saying much.
Several YouTubers have joked that the best actor in the film is the football. Which is true.
Greg Ellery clearly knew what kind of movie he was in and his melodramatic performance as Steven brings life to the plodding birthday party.
Mike Holmes (Michelle's boyfriend Mike) spends the entire movie aping Jim Carrey, clearly playing for whatever sympathetic laughs he thinks he might get.
Dan Janjigian's performance as Chris-R is delightfullyover-the-top. Some YouTube commenters have theorized that he was a real drug dealer who just started pointing a gun at Denny and not an actor at all.
According to script supervisor (and possible ghost director) Sandy Schklair, everyone knew full well what kind of movie they were making. Well, everyone except Tommy Wiseau.
Ho Yay: There's a bit between Johnny and Mark in the beginning, but it's quickly dropped in order to make room for the love triangle plot that drives the rest of the movie.
How about all the attention Johnny lavishes on Denny?
Mark and Johnny wrestling/whatever it is that they're doing at the park, and their run in which Johnny yells, "Catch me!" as if this is all extended foreplay.
Kevin Murphy refers to it as a prelude to "the longest, most explicit sex scene in the movie."
Marty Stu: Johnny. Throughout the movie, he never actually does anything, other than have sex, buy some roses, and throw a football around. Everyone else's characters are defined, primarily, by their relationship to Johnny, and he somehow managed to land a major hottie, at least until he Ate His Gun.
Also, barely a scene passes without someone saying how great Johnny is (with how beautiful Lisa is coming a close second). The man can't even buy flowers without being told how wonderful he is.
One-Scene Wonder: Chris-R. He's not the only one, though. Characters drift in and out of the film like a fever dream.
One True Threesome: Lisa, Johnny, and Denny seem to have a suspiciously close relationship regardless of being surrogate family. Denny even comes and hangs out in the bedroom with them for a while when they clearly are working up to sex.
Nothing between the second sex scene and the birthday party has any actual effect on the plot.
There were at least two or three establishing shots during one scene that took place in the same setting.
Probably the most obvious form of padding used is that of having characters essentially repeat scenes with only a few details changed. This is especially obvious when it comes to Lisa and Claudette, whose conversations with each other are always about virtually the same thing, and with Johnny and his friends tossing the football back and forth.
One odd scene from the middle of the party lasts only a few moments, and is just a shot of the city with the theme music playing. It has no bearing on anything, and might have been used just to denote that time had passed.
The Scrappy: LISA. Everyone in the movie's annoying due to their bad acting and/or stupidity, but she really takes the cake. Her annoying, repetitive mother Claudette and idiot not-boyfriend Mark come in very close second.
So Bad, It's Good: The film has become a cult classic for being so bad it's good - no, more like So Horrible It's Epic.
Squick: The rather graphic sex scenes between Lisa and Johnny. We see far more of Wiseau's particularly unappealing body than we need to. Actor Greg Ellery states that the Squick goes behind the scenes as well. The actress who plays Lisa was only 23 years old. Wiseau was 47.
More to it than that. Apparently Wiseau wanted it to be realistic, so he actually was completely naked while they filmed that scene. That's why he seems to be having sex with her naval - he wanted to make sure he didn't accidentally...erm get it in there.
There's one scene where Lisa's neck starts strangely spasming!
Unintentionally Unsympathetic: Johnny, who comes off as creepily obsessive and a douchebag rather than the model husband Tommy Wiseau intended him as. For instance, he laughs at the thought of a woman getting beaten up and going to the hospital (and it's not one of those awkward, WTF "are you serious?" laughs, we think), and later on, while claiming he never hit Lisa, he shoves her onto the couch when she is ready to walk away.
Wangst: Johnny is especially guilty of this in his dialogue.