Besides the ones already mentioned, one that tends to grate me is the idea that Spike was this master manipulator that was constantly manipulating and gaslighting Buffy in S6, and similarly the idea that Buffy was incapable of making her own decisions and was this "pure" victim sullied by the dirty, disgusting soulless thing (there is the opposite side of the spectrum as well, but this is rarely an argument coming from anti-spuffy people, though I've seen that case as well).
- I don't believe Spike truly manipulated Buffy in S6 because he actually believed what he told her to be true. He wasn't right and was kind of deluded about it, but it's what he believed, not something he used knowing full well it wasn't true. Buffy isolated herself from her friends, he mostly saw what she was doing and ran with it, but as he says in NA, he would've accepted either way. Don't get me wrong, he spirals out of control as Buffy starts moving away from him, but even then he never behaves as a moustache twirling, Machiavellian abuser.
- Buffy being depressed does not mean her actions and choices aren't her own. She may feel powerless, but she has power, whether she wants it or not (which is kind of the whole point of Dead Things, and her whole arc overall). She was the instigator of most of their sexual encounter and was very much proactive in how and when they happened. She shocked a 120+ yo vampire with her rough sex, for christ' sake. She is not a virginal, helpless little girl. We finally get a female protagonist who is given a complexity and grey behavior usually reserved for male characters, and people want to make her a victim again (we had that with Angel, we don't need a repeat).
Both screwed up, both behaved badly due to their own issues, and both hurt the other as a result. But I don't believe either was ever intentionally inflicting pain because they wanted to see the other suffer. They did what unfortunately a lot of people do in relationships, which is to lash out when they're feeling powerless, hurt or insecure.