When I learn the following about a person, regardless of my would-be relationship with 'em, it makes me want to run as fast as I can in the opposite direction... (OK maybe not always, as some of these items are less crucial than others)
1) First and foremost, any form of right-wing ideology (or authoritarian bootlicking in general), especially when they make those views a defining part of their identity at the expense of, y'know, having any legit personality outside of politics
2) Affinity for psuedoscience woo BS (anti-GMO, anti-vaxx, "wEeD cUrEs cAnCeR", etc. - there is often a bunch of overlap with the first group)
3) No sense of humor and refusal to engage in some light-hearted back-and-forth trash talk (to me, casual roasting in good fun is the mark of a truly solid friendship)
4) Lack of passion for intellectual or creative pursuits, preferring to devote their time entirely to physical hobbies, especially "Chad" or jock activities. It's important to have a healthy mix of both mentally and physically-engaging pastimes, although I definitely lean more toward the former.
5) If they're invasive and don't respect boundaries, or call me without giving me a few minutes of advance notice
6) Being a psychiatrist, especially if they work for a loony bin (of course this is very hit-or-miss; there are some world-class professionals out there with hearts of gold and great heads on their shoulders. But personal experience has taught me time and time again to distrust the psychiatric-industrial complex. This has zero bearing on psychologists mind you - I'm a living testament to the power of a good talk therapist.)
7) If they blindly hate a genre of music on principle (especially metal, punk, or rap), without having spent a decent amount of time diving into it. The two exceptions to this are bro country and NSBM - the less said about those two abhorrent tripe genres, the better.
8) When I learn a... "person" has Borderline Personality Disorder, I instantly lose any and all respect I might've had for them. Invariably, my experiences with these manipulative, abusive pieces of human detritus have been taxing on my sanity at best, and outright traumatic more often than not. I'm sure there are a precious handful of individuals on Earth with BPD who actually are cognizant to just how toxic and corrosive they've been in the past, and devote the rest of their lives to atoning for their atrocities. I salute them. But they are the exception, not the rule. When someone is a Borderline emotional terrorist, it's their loved ones and those around them who truly suffer from it. Something to which I can attest all too well, having my teenage years gleefully stolen from me by "mommy dearest"... I won't get into the sob story here.
9) Speaking ill about me behind my back, especially to my other friends. You already know how Autists like myself don't do "hints" or subliminal BS, so why not say it outright? I can take it. If you have an issue with me, grow a pair and tell me to my face. Or, you can just cower back into your hovel of cowardice and inferiority. A couple weeks ago, this already-close friend I made working at a theater company last summer told me that one of my only friends from high school asked him "yo what's with [Bapho's] duck walk?" ...they're both coming down to hang out Saturday, ironically enough. I intend to drop a real zinger on that rat bastard and grill him about this, when the moment is right...
10) Finally... if they aren't 420 friendly. Now, preferring not to smoke the devil's lettuce is one thing; I have nothing but respect for those who choose to abstain from the substance. More for me, y'know? But if you're gonna be all Gestapo about it, moralizing about weed with outdated scare tactics and misinformation, I'm gonna double down and take a hit off my next blunt even harder, just to spite you. I revel in "DeGeNeRaCy" and if you wanna get in the way of that, you'll have to kill me first.