I know almost everyone’s currently raving about Dipper/Author parallels and honestly they might have stuff in common beyond mystery solving we don’t know yet, but the show has made it abundantly clear at this point that there are many similarities that exist between Stan and Dipper. Stan himself has literally told us that he sees a lot of himself in Dipper. Dreamscapers is a whole episode dedicated to this.
[look little Stan even has worry lines around his eyes like Dipdop does]
Stan was bullied as a kid and I’m betting Dip’s given a hard time by his peers too (we’ve already seen him harassed by Robbie). Both of these guys want/ed to be stronger, and even though they don’t like the methods their father figures go about making that happen, its really paid off for them
[Dip’s even punching with this left fist too]
Boyz Crazy is another episode we see obvious parallels. Everyone seems to think Stan was this huge flirty ladies man jumping from crush to crush when he was younger but?? i’m pretty sure Stan has been in love with the same girl since he was a dorky teenager
a lot like another dorky pre-teen we know
[neither of them really ‘get’ their girls either]
Dip and Stan are both arrogant and stubborn as hell, and that’s why I think they butt heads a lot of the time. [‘The kid’s stubborn, that’s his problem. Sorta like me, I suppose.’]
They like to see themselves as heroes
And they’re wildly determined to achieve their goals (to an obsessive degree I’d say). They’re definitely not afraid to get their hands dirty in the process (ie. cheating, lying, and revenge).
At one point Stan yells at Dip 'Your dumb obsession is going to get us all in trouble one of these days!’ and he’s right—Dip trying to find the Author and prove himself to the public does get them into trouble—but its pretty ironic that Stan's nearly identical obsession has gotten them all into major trouble now too.
Grunkle Stan is a pretty selfish, greedy guy, but when it comes to his family he’ll drop everything to help and even fight if he has to. The same goes for Dip. Protecting Mabel is pretty much always his first priority. He sacrifices everything for her well-being (mystery solving, his crush on Wendy, his life, etc.) so that she’s happy, with the exception of Sock Opera which was necessary so that Mabel could realize she hadn’t been returning the favor.
[i’m gonna point out in the above photoset, the dialogue Stan says in Scary-Oke is the exact same Dip says at the end of Sock Opera ('everything hurts’). not sure about the significance, but TV Tropes has this parallel listed as a 'meaningful echo’]
Stan might be more ‘fun’ per se, but he’s much more cynical and practical like Dipper is, compared to Mabel’s eternal optimistic idealism.
Any time she does something silly, Stan and Dip are usually responding with a snarky comment. This pragmatism vs idealism is especially made apparent in Boss Mabel, when Dipper’s about the business and Mabel is about making people happy (which is why she ends up being a terrible boss).
It seems this fandom just assumes Stan isn’t smart, but I’ve never once thought that? He’s incredibly cunning, clever, witty, and intelligent—a lot like Dipper and Gideon too. Gideon is listed as both Stan and Dipper’s evil counterpart. The personality similarities might explain why these three men are right next to each other on Bill’s Wheel, but I digress.
honestly I could go on and on here. there’s just so many parallels drawn between Stan and Dipper, and as we all know by now nothing in this show is highlighted unless there’s a reason for it.