PETA in "Psychic Octopus & Oil Spills". Matt insultingly calls them "nutjobs that do just about anything to get their name out there".
Matt has taken several shots at Donald Trump since he began running for president.
In "10 OPTICAL ILLUSIONS That Will MELT YOUR MIND!", Matt talks about an optical illusion that makes the viewer think that pink dots that form a circle have disappeared. He then ponders if the effect that makes them appear to disappear works on people, because he'd love to try it on Trump to see if he disappears.
Acceptable Professional Targets: Lawyers in "20 Haunting Halloween Facts". Matt says that there are real-life vampires, who drink people's blood and claim to drain people's lives. He then says that they're better known by their day name of "lawyers".
All 10 religions discussed in "The 10 CRAZIEST Religions in the World!", such as Jediism and The Church of Euthanasia.
He criticized the Catholic church in "Text The Pope!" for their alleged pedophilia.
Accidental Innuendo: In "Star Wars in 3-D!!!", Eugene asks, "Like my lightsaber?", the lightsaber being a laser sword from the Star Wars franchise. He then says, "Yeah. It's real." The lightsaber seems to be phallic, making it seem like Eugene is bragging about his penis.
Is Hugo really insane, or is is he an intelligent Cloudcuckoolander who just has a terrible way of communicating things? Or both? For example, in "Psychic Octopus & Oil Spills", Matt takes an hour to figure out that the answer to a math problem is 7. When he's done, before he announces this, Hugo comes in and says that it's obviously 7.
Eugene is supposed to be smart, but is he really? In "Star Wars in 3-D!!!", he requires a calculator to solve a simple math problem.
Lorrenzo claims to always "get some bitches", but it's possible that he's actually a Casanova Wannabe and is merely lying to make himself look cool. After all, we never actually see him outside of Matt's house.
In "Q&A with Matt #3", Matt is asked by a fan what the most shocking thing he's discovered is, and he says it was a troll in his butt. Was he talking about the mythical creature, or an internet troll? Given how much Matt criticizes the latter kind, it would make sense for Matt to be shocked by it.
Some viewers have theorized that Matt is actually Hugo's failed clone, rather than the other way around.
In "20 Ways to Lose Your Card", Matt lists 20 ways a man can lose his man card, a symbolic representation of one's manliness. The man card is seen as a good thing by Matt. Did Matt intend this as a mere comedic video, or was he using the Straw Misogynist trope as a Take That! against misogynists?
Angst? What Angst?: Hugo frequently gets locked up and yelled at by Matt, but is usually happy when he's seen outside of his cage.
Big-Lipped Alligator Moment: In "Reasons to Celebrate!!", Matt lists ways he and his fellow Canadians celebrate Victoria Day, and then suddenly starts dancing to the song "Apache" by The Sugarhill Gang. He then continues talking about Victoria Day. This moment where Matt dances is never mentioned again.
Bizarro Episode: "Bacon Flavoured Thoughts!". The usually-sane Matt acts like a crazy person, and rambles about how bacon is fantastic. This contrasts his other videos, where they have some kind of plot, and Matt acts like a normal person.
Some of Matt's fans have gotten into arguments over whether Matt should start a gaming channel. When he did however...
The revelation from Grade A Under A that Matt had plagiarized on some of his lists. Without going into details, this did result with a slew of people losing respect for Matt, some people constantly complaining despite Matt owning up to his mistake, and some taking the third option and watching his videos and not giving a damn.
Captain Obvious Aesop: In "20 Socially Unacceptable Things", Matt tells the audience that it's bad to pick your nose.
In "20 Reasons Why NOT to Be 'In Da Club'", Matt says that if you're at a club and you fall anywhere, you should just assume you have AIDS or herpes, because of all the broken glass lying around. In reality, falling on broken glass lying around is extremely unlikely to give you AIDS, as that has only happened a few times.
In his "Top 10 Coincidences" video, while talking about the uncanny similarities between the Titanic disaster and a book called Futility, or the Wreck of the Titan released 14 years prior, Matt pronounces "Newfoundland" exactly as it is written rather than its real pronunciation ("NEW-finned-lind"). The comment section lost their shit over it.
In Top 10 Deadliest Natural Disasters, he refers to the city of Christchurch as "The Christ-Church", and says (While talking about the February 2011 earthquake) that an earthquake had happened to the same city 6 Years before. That earthquake had actually happened Six Months earlier in September.
Fanon: It's never outright stated in Matt's videos, but it's a common fan theory that Hugo, Matt's clone, has the last name Santoro, which is also Matt's last name.
"Funny Aneurysm" Moment: In The Stinger of "Star Wars in 3-D!!!", a fan commenter asks Matt, "You like the beatles right?". He turns around and looks at his posters of The Beatles, and when he turns back to face the camera, he has Beatle hair and gives the commenter a thumbs up. This is Played for Laughs. It became less funny when Matt revealed that he actually isn't a big fan of The Beatles, and that the posters belonged to Marci, his then-girlfriend, whose relationship with Matt ended not too long before Matt revealed that the posters weren't his.
On Valentine's Day, 2013, Matt made a vlog to his then-girlfriend, Marci, about how much he loved her, and how he looked forward to spending his life with her. About a year and a half later, they broke up.
On Matt's vlog channel, he made a video called "Something Really Cool Happened Today!". Several hours after the upload, Robin Williams committed suicide, so it looks awfully and horribly misleading. Matt came to acknowledge this in the next vlog, which was a full-on tribute for Williams.
Matt's phone conversation with a random stranger in "How to Start Off 2012 Right!" goes surprisingly well, which is very heartwarming.
Matt's one million subscriber vlog. He shares the legendary moment with us by refreshing his computer and watching his sub count roll over into seven digits. He spends the rest of the video gratuitously thanking the audience for all that they've done, and even starts crying in the middle of it.
In The Stinger of "20 Jolly Christmas Facts", Matt gives Hugo a hoodie with his name on it for Christmas, since he hasn't been very nice to him. Hugo gives him a fish head, which means a lot, since Hugo loves fish heads so much.
At the end of "Balance", Matt doesn't feel like doing the face, but he does it anyway for the viewers.
In "My Make-A-Wish Foundation Experience", he talks about Jonas, a kid with mitochondrial disease whose wish was to meet him. He says that Jonas told him that Matt's videos are the only things that make him happy when he's sick in bed. That's extremely heartwarming.
"The Death of Robin Williams." is mostly tear jerking with all the talk about the suicide of Robin Williams and suicide in general, but it's heartwarming when Matt says that he and the audience can start a conversation about getting help for suicide in the comments section.
All of the endings of Matt's Q&A videos, where he mentions how he had to answer so many questions. It takes dedication to answer questions from fans for 2 hours.
At the end of "A New Planet & Antimatter!", Matt gets killed by the anti-matter container being dropped by Eugene, and St. Peter implies that Matt will go to Hell, since he was never nice to Hugo. But then, Matt mentions that he was just about to get 1500 subscribers, so St. Peter lets him go back to Earth!
In the beginning of "20 Valentines Day facts", Lorrenzo throws petals in celebration of Valentine's Day. It's heartwarming to see a man so obsessed with sexual love focusing on the beauty of romantic love.
After Matt made a tearjerking confession about his suffering during his abusive relationship with Nicole Arbour. Many YouTubers came to his side and defended him. Rob Dyke was infuriated by her abuse of his friend, Boogie2988 admired Matt's bravery and confessed his own experiences with domestic abuse. While Matthew and GradeAUnderA have an unpleasant history between each other, he's given his support through Matt's confession and has sided with him during the feud between Nicole and Matt.
In "Casino Heist & H.I.V. CURED!", Matt made a prediction that Miley Cyrus would spread STIs, because she had just turned 18 and so would soon start having sex. Now that Miley Cyrus is known for being risqué, Matt's prediction hits close to home.
In "So Many Presents...So Little Time!", Matt shows the audience a Batman money clip he ordered, and tells the audience not to mistake it for a Batman ninja star. This became hilarious when his viewers started sending him ninja stars in the mail as a joke.
In The Stinger of "Drake NYC Riot!", one of the YouTube comments Matt shows from his previous video tells him that he needs to grow a beard. 2 years later, Matt posted "Why Beards are Awesome", where Matt says why his Badass Beard is important.
Matt and Eugene have this whenever Eugene tries to use a lightsaber against Matt, especially with the phallic nature of the lightsaber.
In "Raygun vs. Fire!", Hugo uses his ray gun to turn Eugene partially invisible, possibly as a playful way of saying that he likes him.
In "Autumn is AWESOME!", Matt tells Eugene that if he tells one more cheesy Halloween joke, he'll punch him right in the dick. One can only wonder why he would do that...
In "500 MILLION!!!!", Big Shine demands that Matt explain himself, because he hasn't put up a video in 2 weeks. You can't help but think that Big Shine likes Matt as more than a friend and really wants to see him on screen.
In "The End of the World!?", Matt and Hugo dance together, until they realize that the camera is still on and the audience can see them.
In "World of Warcraft BEATDOWN", Big Shine beats up the 8-year-old Timmy Burns just because he left a troll comment on one of Matt's videos. If he believes that Matt's videos are that important, then it may be an indication that he has romantic feelings for Matt.
In The Stinger of "Time to Rewrite History", Hugo and Eugene dress up as each other, which raises some questions about their relationship.
In "Star Wars in 3-D!!!", Hugo wants to do the outro screen for Matt, possibly because he wants to be like Matt, which might indicate that he has feelings for him.
In The Stinger of "500 MILLION!!!!", Matt dances with an unnamed male, and the 2 of them seem to enjoy it.
In "THE GREATEST EVAR!", Matt talks about the 2010 divorce of Mary and Al Gore, and calls it ridiculous. He says, "I mean, how could you not want to be with a guy like Al Gore? He's so exciting!". He then adds, "And sexual" in a seductive voice, which seems to indicate that Matt has homoerotic feelings for Al Gore.
In "Q&A With Matt #5", Matt says that the prime minister of Canada, Stephen Harper, is the 2nd-sexiest Canadian (behind Matt's ex-girlfriend) and "a heartthrob".
In real life, fans poke humor about how Matt and Rob Dyke are this. They are amused by it.
In the beginning of "Triumphant Return!", after a month of not having made any videos, Matt walks into the room with music playing, whilst wearing sunglasses.
At the end of "THE GREATEST EVAR!", Hugo escapes from his cage and attacks Matt, who locked him up for no apparent reason.
In "20 Jolly Christmas Facts", Matt says that it's impossible to stop time, but Eugene comes in and stops time for Matt. When he starts time again, Matt doesn't even notice Eugene!
In "Winter is WICKED!", Matt is disappointed that there's no snow, so Eugene uses his warlock powers to make it snow.
In "20 MORE Ways to Lose Your Man Card", a bear walks in to Matt's house, so he punches it.
Narm: In "100th Video Spectacular! (MEGA COLLAB)!", Matt Watts makes a point to emphasize how great Matt Santoro is so the audience doesn't take it the wrong way when he tells them why Matt Santoro is weird. He says, "[I] love [Matt Santoro] to death!", which makes it sound like he's trying too hard.
Narm Charm: The intro used in videos like "Pirates 4 FTW!" is fast-paced and looks funny when the words "Matthew Santoro" show up on the screen in only a few seconds, but it fits the comedic tone of Matt's videos.
The video "Halloween" makes more sense when you watch it knowing that there's a Screamer Prank at the end.
In the beginning of "A New Planet & Antimatter", Matt pats his body, and says, "Woah". This doesn't make sense until the end. At the end, Eugene breaks the container of antimatter, which kills Matt. Matt convinces St. Peter to let him go back to Earth instead of Hell, since he was just about to get 1500 subscribers. He goes back, pats his body, and says "Woah".
Some Anvils Need to Be Dropped: The aesop in "The Death of Robin Williams." is that suicide is never a good solution to depression, which Matt explicitly states. If Matt had implied rather than clearly stated this lesson, then some of his viewers wouldn't realize the moral.