I love the idea that if Tara was still with us in season 7 she would been the voice of reason and would be protective of Buffy because she can see what Buffy going through because she sees the human side of Buffy where now the Scooby gang sees the hero the slayer first human being second.
I think that's the key, Tara saw Buffy's Human side first and the most, and also, the way she knew Buffy didn't know her that well but still stood up for her and then called her family. I feel that meant a lot to Buffy.
It's a shame we didn't see Buffy and Tara hang out more because I feel like their dynamic is low-key but very understanding of each other.
Also, I know the Scoobs have been there for Buffy a lot but I don't think Willow and Xander showed up for Buffy the way Tara did in season 6. (I think the only other one who did was Cordelia, not always tactfully but she did try to defend Buffy during that shindig with the mask and when everyone was being horrible to Buffy).
Tara was amazing running interference between Buffy and Spike and she always approaches things with such compassion and understanding and I don't think Buffy has that a lot. And, man did she need that kind of thing in season 7.
(And apparently, in season 8 comics when her friends forcibly pushed Buffy backed into the closet. I still can't believe they did that but also, I believe it because... Whedon).
TLDR, Buffy, and Tara friendship supremacy.
