Okayyy random gravity falls thoughts about Bill and his relation to each of the Pinesssss...
We know Bill likes Mabel very slightly more than the rest of them because of her fun and chaotic nature, something that Bill strives for— happy and unconcerned about his past. Mabel is what he wants to be, a chaotic force that isn't held back by the trauma of what he did. But we can tell in his more candid moments that he is not what he portrays.
Ford? Duh. Their ego, their thirst for knowledge, their need to be better than the others that put them down for their differences— plus through all of their rocky relationship, we know why they liked eachother on some level. They were eachother's gratification and reassurance that who they were wasn't bad. That's probably one of the big reasons as to why Bill freaked out so much when Ford didn't want anything to do with him anymore. He needs him, needs Ford to be his witness.
Stan and Bill— great foils. Con-men that lie, cheat, steal, it makes sense that Stan was Bill's final undoing. He could see through Bill, you can't bullshit a bullshitter. But Stan did it for family, Bill did it for himself. That's why Stan came out on top, he had people there for him to help him through it.
But Dipper? People seem to have more mixed opinions here, that they don't have a lot in common other than great "I hate your guts" chemistry. But in my opinion, I think Bill hates Dipper because he reminds Bill of his younger self.
Hear me out— obviously the same is true with Ford, but when F and Bill met, Ford had already found his confidence. Egotistical or not, he had 12 PHDs, was currently in the middle of a giant scientific breakthrough, and had fallen into some self-centered traits that Bill resonates with.
But Dipper? Who wanted to see beyond the world presented to him, had a feature he was frequently ostracized for (that literally represented the stars 👀), and has a soul deep anxiety and fear of rejection? Dipper absolutely reminded Bill of his younger self. The younger self that destroyed his world, that event he has spend his entire life trying to escape. Ford was too old to really trigger that too much beyond relatability, but Dipper was 12. He was young and in Bill's face with his determination, physical difference, love of his family, slightly darker tendencies for vengeance, and desire to show others he was right.
Dipper made Bill so angry, that he would throw him off a water tower, because he was everything Bill lost and regretted and refused to even acknowledge anymore. And seeing Dipper with everything young Bill had wanted? Pissed. Him. Off.
