Also Faith has already turned down Spike because, in her own words, she'd matured. Buffy hasn't ( at least in the romantic sense) so she embarks on yet another doomed vamp-relationship. Because they always end so well. 🙄
Agreed, in fact going from Angel to Spike, considering that he was a soulless bum who only cared about drinking and sex when they first hooked up, could be considered devolution in her romantic choices. In fact, she basically shit all over Angel's sacrifice to give her a normal life by turning around and getting with not only another vampire but one she knows to be his personal rival, or in general someone lower than him. So the feeling of being insulted among other things that I personally got from him in 'Chosen' is the one fragment of his visit that I can actually condone.
When Buffy uses sending Angel to hell as an argument against Xander (regarding Anya) in season 7 was actually the only mature moment Buffy had in pretty much the entire series. I was quite impressed with that but then when it came to Spike she went right back to being immature, even more so than her earlier days and biased at times. Like when Faith showed up and she didn't want a murderer staying in her house, around her girls when she'd been keeping Spike in her basement for at least half the season.
😛
She kind of did the opposite with Spike from what she did with Angel, she became blinded to his true nature instead of her eyes being opened to it; when he was killing/turning again under the influence of The First, there may have been some solid evidence to suggest the influence (such his not having any memory of the attacks though at least one victim and one witness had identified him) but that didn't make it valid that she refused to entertain that he was guilty. With or without a soul he was pretty much a sociopath. She never even saw him as much of a hero until she watched him die while using the amulet in the finale. It was
AtS where he more became a hero (big surprise, everybody grows more healthily on
AtS; Angel himself
, Cordy, Wes, even Harmony a bit in season 5, then Spike).
Sorry this is very off topic, so I'll get us back on by making this statement; Faith may have been a careless party animal in the beginning, but I do buy it when she tells Spike that she's matured in season 7. The way she told off The First when it had appeared to her as Mayor Wilkins, the one person who captured her heart only to end up wanting to use it proved that she's above users now and with Buffy as the only exception Spike was nothing but a self-proclaimed player.
True I did forget about Angelus in S2. But back then it was at least accidental to start with (not a conscious choice on Buffy's part) and she was 17 and emotionally distraught. Buffy comes to regret letting Angelus live by the time 'Passion' rolls around, and pays the price for it in 'Becoming'.
Considering that Angel was her first love, and first love is supposed to be naive and full of irrational choices, as a lovestruck teenager I can ever slightly give her a pass for her immaturity regarding him but as a slayer it was selfish and reckless of her to let her feelings for Angel get in the way of her duty against Angelus. That I believe is the reason for Angel's revelation that their relationship was dangerous, because he saw her unable to do was what was needed when facing Angelus, something he tells Gunn in
AtS (though I am totally spacing on the episode and incident) is what earns his utmost trust.