How did Angel interfere with Buffy and Parker's relationship? That was when Buffy tried to move on.
Quite simply, Angel didn't know about Parker.
He took pains to stay in the shadows during Pangs, one might think he was being an ass about it but he was trying to help in as unobtrusive way as possible.
Yet, he lets everyone else close to her know about his presence, enough that it realistically would have been impossible to keep it under wraps. Plus, he could see her, but she couldn't see him. The unfairness of this situation is not lost on Buffy, as she confronts him about in LA.
I mean, later he beat up Riley I guess but I wouldn't characterize the events of 'The Yoko Factor' 'trying to make Buffy miserabl'e, Angel was trying to apologize, messed it up and then left town again. He never saw Buffy again until Riley was well out of the picture.
Again, even Buffy calls him out on his behavior in this episode. He was out of line, largely because he saw a capable human rival, but this isn't specifically what I mean by Angel making Buffy's life miserable. It is, however, a part of it.
In fact how did Angel interfere with the whole Spuffy mess? He only became aware of it by the end of S7, he and Buffy had one conversation and then he left her.
Angel can't interfere with what he doesn't know. He did know about Riley. He didn't know about Spike, as you say, until the end of season 7. Once he did know, though, he acted like an ass again. You say he left it alone, but did he? Buffy reasoned that he needed to be her second front if hell broke loose. I think this made sense to Angel. Moreover, Buffy gave a non-committal answer about Spike, and left Angel just enough hope for him to leave happily. I don't think he believed Spike had much of a chance.
Angel is not the cause of any of Buffy's misery in S5-7. Spike is the cause of a great deal of it.
Angel isn't the cause of Buffy's misery in seasons 5-7, but he did account for a lot of her misery is 1-4. Moreover, the causes of Buffy's misery in each of the last seasons stand thus: 5) Joyce's death/protecting Dawn, 6) being resurrected from heaven and feeling disconnected, 7) having the burden of stopping all hell from breaking loose, plus the protection of a bunch of young girls.
Even if you could argue that Spike was responsible for some of Buffy's misery in season 6, he wasn't all of it, and there is a large part of it where he is giving her some kind of solace. Remember, she almost committed suicide atop the tower. If she had not found a confidante in Spike, she may have tried again, more successfully. It was clearly a depression she couldn't share with the regular gang.
The first thing Spike tries to do is Harmony, actually.
LOL, yes he does. To me, after all that was said in season 7 of Buffy, this is the biggest character shift, and a difficult one the writers have to explain. If I accept it at face value, though, he does start toward Italy right after this, only to realize it's a damned awkward thing to explain. Let's also count how many times Angel monkeyed around, and though it's unworthy of him, Spike is more or less using Harmony as a release, rather than having genuine affection for her. Again, not the best translation from one show to the next, but still a salvageable point.
The such a radical misinterpretation; Spike got played by Lindsey. He straight up admits it after the fact. But before that he was very much buying into Lindsey's ploy, though Lindsey's 'fake Doyle' had to do a hell of a lot more than actual Doyle.
I'm not sure what point you are trying to make here. If he accepted the role as champion, then he was doing good. If he suspected that he was being played, then, again, he was still doing good. I am inclined to believe the latter, because he did do a taste test on Cordelia. It wasn't just him covering for his ego later. Just because he liked the idea of being a champion doesn't mean he bought the whole story, just that, on some level, it appealed to him.
That isn't really the question, but what about some kind of heroism away from Buffy. Angel showed that from the start, Spike spent a long time being a complete ass, and only became a 'champion' because he was manipulated into it as part of an evil scheme.
Spike only seems to do good for his own reasons post 'You're Welcome' really.
Again, Angel did not show this from the start. He spent the better part of 100 years struggling just to exist without causing harm, and still had trouble with the new lifestyle. Remember the diner in the 70s? Remember the woman with the men in the street in the 1890's? Remember him reconnecting with Darla and trying to make it work as part of the group, simply because he was lonely? It was a long struggle for Angel, and, in the end, it was Whistler who showed him an alternate path. I put to you, why is Buffy or Angel showing Spike a better path any different than Whistler showing this to Angel?
Spike did choose to do good on his own. Yes, he watched over Dawn for Buffy's sake, but he never had any expectations of her being resurrected. He had no hope of being rewarded for this. This was all on him. Also, he helped the Scoobies, who he loathed, simply because it was what Buffy would have wanted. Again, there was no hope of reward for this. Just because Spike carries on in Buffy's memory doesn't make his decision any less worthy than Angel adopting the lifestyle because he sees a vulnerable pretty girl with a great burden.
After getting a soul, Spike continued to help Buffy. Yes, this was with Buffy, but his ultimate sacrifice at the end was, again, without the hope of ever being rewarded for his efforts. He literally just wanted to save the world. You can't enjoy bonus points with your ex if you're dead.
As for his stint on Angel, Spike did choose to help. It isn't like the series ended with him refusing to help anyone. There is a great deal of introspection Spike goes through with regards to the evil he has done as a vampire. Remember the bit with his hands being chipped off? How about helping Angel with the necromancer? How about saving the baby from the ritual? Spike does choose to do good without Buffy. Why should it matter that he happens to be doing this with Angel? The result is the same. He's still choosing to do good.
