Diana's relationship with Julia Kapatelis for much of Perez's run. Julia became a second mother to Hippolyta (and it turns out she was fated to.)
The reveal of how protective Myndi Mayer was to her younger brother Kevin, seeing as they were both ostracized from their family. In Myndi's case it was because of how flamboyant and passionate she was, in Kevin's case, it was because he was gay. Myndi was the only one who accepted him and convinced him not to be ashamed of who he was. In fact, when their sister Lili refused to invite Kevin to her wedding, Myndi passive aggressively threatened to use her influence to turn the whole thing into a giant scandal if Lili didn't reconsider. It becomes sadder since this info was revealed after Myndi died of a cocaine overdose, with Kevin explaining the reason Myndi left him nothing in her will was because he once said all he wanted was for her to blow out the candles on his eightieth birthday cake. That was back when they were kids. And Myndi still took him seriously.
The overall theme of female friendships from George Perez's run.
First, there was Maxine Sterenbuch's devotion to Valerie Beaudry, her longtime pen pal and closest friend. For as long as Valerie was a villain while the Silver Swan, Maxine did everything she could to try and save her friend from the abusive influence of Henry Armbruster.
Christine Fenton being Myndi Mayer's closest friend and confidante since college due to how blunt and honest she was, being able to see through Myndi's bluster. Christine was later given the main controlling shares of Myndi's corporation after her death.
Second, despite that Vanessa was acting pretty crummy to Eileen Flowers in exchange for hanging out with Lucy Spears, Eileen never gave up on their friendship and didn't try to pressure Vanessa into picking sides, and proved valuable support to Vanessa when Lucy killed herself.
From Challenge of the Gods, both Diana and Hippolyta choosing to put the past behind them and try to rescue Herakles from his And I Must Scream situation (having taken Atlas' place.)
Herakles then begs the forgiveness of the Amazons. They do, unanimously.
The entire last issue of the arc is full of it (perhaps too much). Zeus and Hera reconciling, Steve and Etta admitting their feelings towards each other, Hippolyta and Philippus reuniting, bearing no ill for their previous encounter and at the very end, Diana returning to Julie and Vanessa Kapatelis.
In Warkiller, Diana realizes that Genocide has used her Emotion Bomb powers to poison Donna Troy's mind, causing her to fly into a delusional, Unstoppable Rage when in proximity to the Golden Lasso of Truth. Without hesitation, Diana tosses her Iconic Item into the sea.
Diana: It is a glorious thing. But it is still a possession. You are my sister. And all the gifts from the gods that have ever been aren't worth a strand of your hair.
Wonder Woman #600 has Diana leading a team of all the superheroines against an army of robots build by Professor Ivo. After, she (very nicely) declines an offer to go to a bar with them or to meet the President in favour of attending Vanessa Kapatelis' graduation.
In the alternate timeline of Odyssey, Diana has been receiving help from a mental projection that, unbeknownst to her, belongs to Dr. Psycho (whom she finds familiar, but does not remember). She's finally able to get him to reveal his real form, as a dwarf. When he sadly does so, her comment is "This isn't so bad, is it?" Since this Psycho is a lot less evil than the main universe one, it's nice to see somebody look past his appearance. It's followed by his speech on how he'd rather go back to being a monster, and her enemy, than live in a universe without her, which is also rather touching.
Hephaestus: And I love you even more than that, son.
Diana telling Hades that she loves everyone, including him.
After being critically injured by the First Born, Diana is visited by Ares' ghost, who offers to take her to the afterlife. She says that she can't, to which he replies with a smile "Of course not. That was selfish of me."
In the climax of Brian Azzarello and Cliff Chiang's run, the Minotaur is ordered by the First Born to kill Diana; he refuses as Diana had shown him mercy when she was much younger.