I know Buffy and Spike would have probably gone quite differently had Angel been there, so this is just hypothetically if Spuffy followed the same path and Angel's presence didn't change anything.

I can make a case for all of these, s4 would annoy him because they gave Spike more help than I can imagine them giving Angelus, they treated soulless Spike more as a human than I can see them treating soulless Angel. S5 it would be frustrating to see Buffy starting to trust him especially with her family who Angel never got close to & knowing Spike loved her (& the kind of twisted view Spike had of love at that point). S6 speaks for itself but I think S7 would be worst. At least in s6 he could blame her depression, I think he'd be more angry or concerned than hurt, but in S7 Buffy and Spike had a deep emotional connection and I think that would hurt Angel most.

I think the using him thing wouldn't have bothered him as much as the starting to care for him thing.

Very creative and interesting pick, as always Vini!

I'm not sure, this or 7.
Thing is, at least in 7 Spike had a soul. For most of season five he was still saying 'as soon as I get this chip out I'll kill you all' he was still evil so to see Buffy start to include him and to trust him with her family I think would really get to Angel.
Especially when Buffy kept him around after finding out he loved her, because as has been mentioned, Spike still had a pretty twisted view of love at that point ("I'll win you over by killing my ex" for example) so to keep him in the gang after that I think would get to Angel too.

Great question! Season 7 the most coz look how peeved he was when he thought Spike was her boyfriend, i dont think he'd like ot catch the live show. And also season 5 for all the reasons stated above^

Yeah, I agree with Sam the pick is very hard and good. So I pick Buffy's close relationship with Spike because Season 7 was the most intense Season of all. And in the Season was about rebuilding and forgiving one another in the past. Also I think Season 6 was another because Buffy was in a tense, sexual violence relationship with Spike and knowing Angel he would never forgive Buffy of what she did.