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.
YMMV: Freelance Astronauts
Accidental Innuendo: Averted/Subverted most of the time, since they really mean their innuendo, but the F-Zero GX LP gives up this gem:
Maxwell: "It's really great when you get to the end of the mission, and you lose because the hit detection on the exit...shaft..."
pipes!: "I HAVE EXCELLENT HIT DETECTION ON MY EXIT SHAFT!"
The name Seaman alone should give you an idea of how many are ripe for the picking in the LP.
"Luigi went up the pipe!" "Did you hear Luigi likes it up the pipe?"
Crazy Awesome: The Kickboat from "The Kickboat Saga". Complete abuse of the Source physics engine + SMod's kick move + Boat + ??? = PROFIT!
Ensemble Dark Horse: PlasmaMan. Started out as some random guest off of the Skype Chat, and became a full-fledged regular.
Good Bad Bugs: Maxwell's "Contra Secret" that he discovered as a child — a glitched part of a level that lets you partially clip though the floor. You can't move anywhere and it serves no purpose, but the young Maxwell was so proud of his discovery he almost sent it in to Nintendo Power.
During their Resident Evil 4 LP, they begin discussing the movie Wanted and it's whole bullet-curving gimmick. Maxwell jokes that the Mythbusters would probably tear the myth apart and then create a robot to try and do it. One year later....
During their Vice City LP, Ferr and Maxwell discuss the fact that because the majority of pedestrians go around doing nothing everyday in Vice City, it'd be easy for a detective to track down Tommy Vercetti and pin him for all his crimes. Maxwell remarks that if there were a detective smart enough to do that, then you'd be playing as that detective, tracking down criminals and shooting them. Sure enough, a couple years later...
Maxwell after hearing about Doomisland's attempt on Master Quest in the Majora's Mask LP, including getting stuck on the Forest Temple:
Maxwell: People listening to this are probably thinking 'Hey, you should go and do a [Let's Play Forum] thread on Master Quest'. Well, screw you, Internet! I'm not going to...
During the Power Stone 2 LP, Pipes is crying out "STOP BUBBLING ME" when he is repeatedly attacked with a bubble blaster. Now consider the later New Super Mario Bros Wii LP where almost all of them at some point will be crying out "NO BUBBLE UP, BUBBLE UP!".
During their LP of Wii Sports Resort, Maxwell and Ferr mention how they wish Nintendo would make a sequel to Pilotwings. Five months after that video, not only is a sequel announced, but its setting is the same one as the game they were playing when they talked about it.
Ho Yay: Between Maxwell and pipes! several times. Once during the Oblivion Let's Play as described by Ferr.
Ferr: For those of you listening at home, pipes! just put his hand on Maxwell's thigh, moved closer and rubbed it upwards while saying "nervous?".
And again during the Kirby Super Star LP when they have Kirby and his Helper CONTINUOUSLY make out with each other (which in the game is a way of restoring each other's health).
Evek: STOP MAKING OUT!
pipes!: I'LL DO WHAT I WANT, WHEN I WANT, WITH WHO I WANT!
Maxwell: It's his hot body.
Then there was pipes! feeding Maxwell an ice cream sandwich during the Resident Evil 4 Let's Play. Later referenced during the Bomberman LP.
And then during the Master Quest LP while in the Forest Temple:
Maxwell: Is there any fire anywhere in this room?
pipes!: ...in my heart.
Ferr: (simultaneously) ...in my pants. (laughter from all four)
pipes!: Wow. Insight into relationship dynamic.
Played around with between Ferr and pipes! during the Master Quest (at 4:20) LP when at one point Ferr mentions how he was saying goodbye to his mother once, and pipes! joked to her that he and Ferr were actually a couple. Later that night, Ferr's mother asked if they were serious.
pipes!: I have a question for ustream! Why are all of these questions like....us-boning-each-other-centric?
Most Annoying Sound: Just try to make it through the entirety of the F-Zero LP without wanting to strangle Evek for laughing at every...little...thing.
The overly long whale "joke" at the end of the Seaman LP.
Most Wonderful Sound: Maxwell's voice, particularly during quieter/calmer LP series such as Seaman or the early stages of Elebits.
Also subverted in Seaman, after a fashion. During the first attempts to name the gillmen, Maxwell simply could not make himself understood, even when using the supplied phrase, even when enunciating (the game uses voice recognition, which before then hadn't been a problem). In the end, it was Ferr who named the gillmen (Apetit and REO Speedwagon), succeeding on his first try after receiving the microphone.
Replacement Scrappy: Some people are disappointed with people like Selic, Ashley and Irregular Hunter being in the group in place of pipes! and Ferr in recent days.
The Scrappy: Lurkdawg was a guest commentator for a session that would end up being two videos. Fans consider him to quite annoying.
Part 12 of the TP playthrough ends with Diabetus recounting two lovely stories about girls that got their faces mutilated; the first had her face eaten by her black lab while she was conked from pills, and the second got a machine caught on her face.
Pipes is surprisingly apt at squicking the other astronauts. In episode 7 of their Master Quest LP, Pipes succinctly describes "tossing a dwarf salad" as probably being like licking the inside of a vacuum cleaner, causing the other astronauts to simultaneously laugh and groan in disgust for about half a minute.
He pulls off another in episode 17 of the Twilight Princess LP.
Maxwell: Ferr, whenever you touch the microphone, horrible noises happen.
Ferr:' Oh, I should stop doing that, then.
pipes!: It doesn't distort your feedback or anything, it just plays Yanni.