Acting for Two: Originally, Chris-R was going to be played by Scott Holmes, who already plays Mike, wearing a hat and glasses, which would have made the film even harder to follow. Fortunately (unfortunately?), Holmes convinced Wiseau to give the role to his roommate, Dan Janjigian, whose performance so impressed Wiseau that he thought about writing more scenes for Chris-R, but never did.
Beam Me Up, Scotty!: The "oh hai, X" construct is used more than enough times in the film, but in the flower shop scene Johnny just says "hai doggie" without the "oh".
The Danza: Subverted if that's even possible to do with this trope with Mike Holmes as Mike. Believe it or not: according to The Disaster Artist, the actor's name is actually Scott Holmes and Wiseau credited him as "Mike Holmes" because he had forgotten Holmes' real name.
Inverted. Lisa has been together with Johnny for seven years, yet was played by a 22-year-old actress. Though her character was probably meant to be older, the contrast of the actress's age with Johnny's Tommy Wiseau being in his late 40s made this all the more noticeable.
Played straight with Philip Haldiman, who was one of the oldest members of the cast and played the youngest character, Denny.
Deleted Scene: The film has only one scene that ended up on the cutting room floor, the original version of the Chris-R scene. Tommy Wiseau insisted on keeping everything in the film, so aside from the aforementioned Chris-R scene (and everything filmed on the HD camera), everything that was filmed ended up on screen.
Deliberate Flaw Retcon: In addition to using the Parody Retcon excuse liberally in defending the film, Wiseau also claimed that Denny's strange, abnormal behaviour was deliberately written in order to indicate that Denny was mentally ill (even though none of the characters in the film seem to find his behaviour particularly out of the ordinary).
Doing It for the Art: Tommy Wiseau. The man spent years raising six million dollars to write, produce, direct and advertise his dream project with absolutely no studio support. The amount of time and effort he poured into making it a reality is nothing short of astonishing - perhaps even inspiring.
Dye Hard: Juliette Danielle, if you couldn't tell from her roots and eyebrows.
That Chris R's actor puts on a better show than the rest of the cast during the 'gimme my fucking money' scene with Denny is apparently largely down to the fact that Wiseau genuinely pissed the actor off between takes.
Greg Sestero's venomous delivery of "Keep your stupid comments in your pocket" is due to him channeling all the frustrations of the shoot, and imagining he was actually saying to Wiseau "Why are you doing this to me?"
Greg Sestero (Mark) is referred to as "Sestosterone".
Mike is the "Me Underwears" guy. But only because that's more succinct than "Hilarious Blowjob Face" guy.
It Will Never Catch On: With a script so nonsensical that the only way to properly salvage it was a complete rewrite and a director who had zero experience in how to make a film, every cast and crew member believed the film would never be seen by any audience, much less get completed.
Judging by her twitter (and corroborated by The Disaster Artist), the actress who plays Lisa, Juliette Danielle, is actually very sweet, unlike her bitchy character Lisa. Not to mention she has a great sense of humor about her part in the movie, and has stated that she LOVED The Nostalgia Critic's review of it.
Most of the cast are this as well, especially Greg Sestero (who appeared on the The Nostalgia Critic reprising his role as Mark). The exception, surprisingly and ironically enough, is Tommy himself, as how he reacts to you depends on when you encounter him.
Method Acting: Chris R's also stayed in character during his entire time on set, resulting in the other actors being genuinely scared of him.
Money, Dear Boy: Sestero considered leaving the set due how difficult it was... but didn't for this reason.
One-Book Author: To date, this is Tommy Wiseau's only feature film, and none of his online projects have gained as much notoriety or cult following.
They Just Didn't Care: invoked As production dragged on, professionalism just fell apart. Most of the crew were convinced the film would never be seen by anyone. Greg Sestero admitted to phoning in his performance. Entire scenes were out of focus because they did not bother to check the lens.
According to a crew member, the infamous "Hai doggie" scene was one of these. The owner of the flower shop they were filming the scene in just happened to have the dog there and it hadn't moved at all during the filming so Tommy Wiseau improvised a brief moment where he rubs the dog simply because the thing was creeping him out.
Sestero ad-libbed the part about the hospital with the beaten up woman being on Guerrero Street (despite being aware that there is no hospital there) because it's where Wiseau's San Francisco apartment is located. Even though no one who saw the movie would ever make the connection, Wiseau was furious at Sestero for this...and used the take anyway because it was the best one they had.
Wiseau insisted on the entire cast being present during the filming of every scene, in case he suddenly felt like throwing them into the background.
According to The Disaster Artist, Wiseau was considering a subplot about Johnny being a vampire with a flying car. It never comes through in the film, but Wiseau is utterly fascinated with vampires.
There's an early version of the film's main theme, which according to Milicevic was rejected by Wiseau for being too depressing. The former interpreted the film as a tragedy.
Word of God: According to Mr. Wiseau, Lisa's mother makes a full recovery from her breast cancer. He's also helpfully clarified that yes, Denny does have some sort of mental disorder, a detail that makes a lot of his scenes make more sense.