In addition to providing the page image, "Basic Instructions", has another strip where both Scott and a customer find common ground over hating going into Scott's place of work.
Parodied in Adventurers!, when the Big Bad pulls the second type of Not So Different moment on the hero in this strip, and has it fall flat almost immediately since the only examples he could come up with were their similar heights and shared penchant for pointy hair. He admitted that he probably shouldn't have made it up on the fly.
Violetta: Really. So you've completely missed the fact that he's overbearing, self-aggrandizing and certain death to be around?
Not said by a villain, but comparing a Corrupt Corporate Executive to his son: Rollie, of Gene Catlow, explains exactly how Steven Avariss is like his father. It boils down to an aspect of their personalities that could be good or bad, depending on how it's applied.
In Erfworld, Stanley declares that his enemy Ansom rules by "violence and fear" (with "just like me" implied though not admitted), not by "nobility" as he likes to believe. Later, it becomes evident that Ansom and Stanley are both fighting for their respective visions of the Titans' will.
Belkar and V definitely have this going on. The characters hate each other and are nearly opposite in personality and intelligence (V is an elfeminate Insufferable Genius; Belkar is macho and rarely thinks before acting, being pure Id). Despite this, the two are practically identical in their readiness to solve problems with violence. In one of V's And That Would Be Wrong moments, he justifies himself by saying that he was only representing "the halfling's" (Belkar's) point-of-view.
Tarquin is this in different ways to both of his sons. He criticizes Nale for allowing his ego to cripple his effectiveness but is convinced that everything is about him, and throws away resources trying to force the world to conform to this, and Elan for being content to be a second-stringer whose main use to his party is his Genre Savvy which is, in truth, exactly what Tarquin is to his own party. He's just convinced himself that he's actually their leader.
Torg: We're her family, Riff. This is her home now. She's not going to destroy it anymore than you would ... with your various nuclear isotopes and biological pathogens ... OK, bad example. Actually, it's not! Riff, with all your dangerous scientific experiments, I put it to you that Aylee is less likely to threaten humanity than you!
Happens a lot in Lightbringer, and the titular character quickly becomes tired of it:
Lightbringer:It's the same damn speech I keep hearing. "You're just like me." "We both want the same thing." 'why are you fighting against me?" The Gentleman told me it. The SmilingMan said he used to be just like me. Werres told me we fought the same fight. And now Darkbringer is using the tired old bit.(...) I'm sick of evil people telling me I'm like them.
Also, one interesting example was when Police Chief Eddie Crane tried to arrest Bruiser, former cop turned into Vigilante Man after death of his kids. Bruiser said he knows what Crane did to murderers of his own family, making Crane left him go.
Sarah from Weregeek recently met a pack of non-geek girls and proceeded to make a rather disturbing discovery.
In Goblins Forgath tries to invoke this to persuade his specist partner Minmax that their new snake-girl companion is in fact a perfectly normal and sound being and thus shouldn't be slaughtered for XP as Minmax is eager to do. Hilarityensues.
In Slightly Damned Angels and Demons appear to superficially follow their associated tropes of good and evil, but the more that is learned about the angels, their magic, talismans and how they interact with demons, the more doubt is thrown onto the binary assumption.
And gives us a strange variation in this strip, where Fuchsia, formerly a Depraved Bisexual succubus and Torture Technician for The Devil, in the midst of a Villainous Crush and a High Heel-Face Turn, listens to her love interest, Criminy, relate a story that could very easily be about Sinfest's main character, Slick, and comes to realize that she has a lot in common with the Damned Souls that she formerly took delight in tormenting. Her response, in a Crowning Moment of Heartwarming, is to sit with the Damned and hold their hands, offering them comfort.
In Drowtales, despite being a Superior Species the drow in particular are not actually that different from the goblin races. Just take a look at how the drow consider the goblin races. Now take a closer look at the drow. Ironic that the ones who consider halmes akin to locusts almost destroyed their own planet for mana-based life a millenia ago, isn't it?
In Advance Wars, there are three main missions in which Black Hole calls this; the most significant is Sonia's A Mirror Darkly, in which she and Lash play a game of chess (with artillery and neotanks, natch), but both of Grit's missions in the Blue Moon campaign section show Lash and Grit invoking this trope, too.
Homestuck: Jade is so frustrated with her newly resurrected dream self that she begins verbally and physically beating her. Then Karkat comes pestering with a "friendly" reminder that this behavior isn't unlike his insulting his past/future self...which she had gotten quite pissed off at him about not much earlier.
Vriska attempts this with Terezi, but given that Vriska has greviously injured other trolls just for fun while Terezi only ever murdered 'bad' trolls or to seek revenge, and given that Alternia is a Crapsack World anyway, it falls flat.
AG: Cause even though you got all these highfalutin morals and fancy reserv8tions, you know as well as me that a killer is a killer is a killer!
Occurs again in the Act 6 Act 3 Intermission when Meenah chides Cronus for bullying Mituna and he points out that she's not exactly a saint either and that in alternate timeline she basically used him to power her spaceship. Meenah struggles to find fault with his argument, but ultimately gives up because she doesn't really care what Cronus thinks.
Another event in that intermission has Porrim deliver a massive social justice rant to Latula, who comments that she seems to be pulling aKankri.
The Renavanna and Eytherlia elves of Ears for Elves, according to Tanna after Zalanna pronounces them feral. The unusual arrangement of panels on that page emphasises Tanna's point.
Zalanna: You see, they live in the untamed wilds.
Tanna: So do we.
Zalanna: In a secret, secluded village.
Tanna: So do we.
Zalanna: With border guards dedicated to not letting a soul in.
Tanna: So do we.
Zalanna: They hide away from any non-elf race, threatening banishment to any who commune with outsiders.
Tanna: So do we.
Despite how much Commander Badass dislikes Canadian Guy in Manly Guys Doing Manly Things, they are more alike than he'd care to admit, in tastes of games, enunciation, and even appearance (to the point that they're Palette Swaps of each other). Emphasized in this comic where, despite having three siblings and two children (and though he doesn't mention them, an ex-wife, a love interest, and a surrogate son), Canadian Guy is the one Commander Badass is most drift-compatible with.