I binged the entire thing a couple of weeks ago & kept thinking I should come on MN to chat about it - here you all are! 
I love seasons 1-3 & 6. Loathe any scene where Riley talks. Tara's just bland - my favourite thing about her is her death storyline, but perhaps that's at least in part because she's not in it! I adore dark Willow, her battle with Giles, Anya round the corner muttering the barrier spell to protect J&A, Xander & the yellow crayon...
I found this time round that I liked Anya a lot more. As a teen I saw her behaviour as weird & against social norms which must be obeyed at all times... As a slightly more self-aware adult, I can see that what irritated me about her was how like me she is, except she lacks the filter I have to maintain to be socially acceptable. I didn't like her because I was jealous of how everyone accepted her asking for explanations about how to behave & how she was able to be blunt & it was ok because she was newly human. It was v interesting though in the flashbacks that she was also seen as odd & socially awkward in her pre-demon days. I hated Xander for leaving her the way he did & I was even more upset that they killed her off & they didn't get their happy ending, although Xander really needed therapy to deal with his issues about his parents' relationship!
I was very definitely team Spike as a teen, but now I just see it all as a bit creepy. Not only did he try to rape her but he also actively pursued her when she wasn't interested, encouraged her to talk to him when she was vulnerable & then took advantage of her isolation from her friends to push his way in. Don't get me wrong, she wasn't exactly angelic in her treatment of him & I can see how the rape thing unfolded - she frequently told him she wasn't interested but then came onto him or gave in when he pushed so I can see how he might've thought that it was the same "no but yes" thing. There came a point where she was very clearly saying no though & there's no excuse for him continuing after that.
I liked him even less after he got a soul though. He was never what she wanted & he never could be, soul or not. If he truly wanted to atone for trying to rape her he should've just left her alone. I think it was the lack of guilt that bothered me the most. In Angel's flashbacks we saw him absolutely destroyed by the guilt of what he'd done, Spike came back & seemed to have gone mad but that was only because The First was making him see things. Once he was out of the school basement he recovered his sanity & carried on as before, even to the point of pretending he was going to kill the principal who was unbelievably hot & had the potential to be a good partner for Buffy. I'd have liked to see a bit more self-reflection from Spike & a bit more brooding. It just felt like the soul didn't really change him that much, whereas he was a total mama's boy before he was turned. It always bothered me that neither Spike nor Angel turned back into a recognisable version of their former selves when they got their souls back. You'd have thought the drunken lout would've coped better with the things he did than the sappy poet.
Other issues I have centre around the whole slayer thing - Kendra said she was given to her watcher at a young age because it's a big deal for her people, yet Buffy knew nothing about it until she was, what, 15? How come Kendra's family knew & Buffy's didn't? Did the families of the potentials know? If not, why were they happy for their teenage daughters to move to Sunnydale & live with strangers? If some random English man turned up on my doorstep & insisted he needed to take my teenager to America because she was in danger from the first evil, I'd have at least insisted on going with her! Surely there's a safeguarding issue here...
In S7 the council are trying to track down all the potentials - some of them talk about having watchers beforehand but others are oblivious of their calling until they're brought to Sunnydale. If they did have watchers, why weren't they better trained already if they could've been the next slayer? Why did the council know about some & not others? How many more were there that hadn't been killed or brought to Sunnydale? How come the council/coven/Giles could suddenly track down more when they hadn't found them already? What happened if a potential became a slayer & the council didn't know about her? Would she just suddenly be inexplicably fast/strong & be in the Olympics before she was tracked down?!
Who was the slayer before Buffy? How did she die? Who was her watcher? What about Buffy's LA watcher, why did she get a new one when she moved? Would it not have made more sense for her watcher to move too?
How come all the potentials were teenage girls? At the end when every potential was imbued with slayer powers they showed young girls so how come they weren't brought to Sunnydale to be protected, or did the Bringers have an age limit? "Oh, we'll only kill the teenagers, don't hurt the babies..." 
Also, they kept going on about "one of us will be the next slayer when Buffy dies" - Faith was the "official" slayer at that point, hence why none of them were called up when Buffy died the second time. I still don't understand why the Council wouldn't have quietly let Faith "die from her injuries" instead of keeping her in a coma. They knew she was a loose cannon & would be a liability if she woke up. They also knew that if Buffy died there'd be no slayer, surely killing Faith would've been "for the greater good", especially when Buffy did die & they didn't know that Willow would bring her back.
I'm totally willing to overlook all inconsistencies & unanswered questions for a programme that has episodes like Band Candy & OMWF. I really want to binge it all again now! DH wouldn't be so keen - I get rather lost in it & it's all I can think about... I need to live real life for a while!