One specifically sticks out in this troper's head. At one point Blue Beetle's younger sister gets separated by an explosion, and it seems as though she'd been killed. We see later that she's talking to someone, when we find out who it is, well it's not good for The Reach:
Milagro: I know you. My brother calls you the crazy one.
Guy Motherfuckin' Gardner: That's right baby girl, I'm the crazy one.
Random Reach Grunt: We're dead.
Milagro also sports the same stupid grin as Guy when he says that.
Also, Jaime causing an amazing Villainous Breakdown for the Reach's Negotiator, who has been monitoring Blue Beetle's signal to ensure he hasn't contacted any of the other heroes regarding the Reach's plans. How does Jaime get around this problem? By sending a letter to Batman and Oracle to clue them in on the plans the Reach have on Earth. Bonus points for getting Dani Garrett, granddaughter of the orignal Blue Beetle to hand it to Oracle personally.
Traci 13 single-handedly averting a mass fridging of the entire supporting cast.
Traci: Hi. My name's Traci 13. I'm dating your son. I brought cookies.
Peacemaker: I'm Peacemaker. This is the Posse. Welcome to El Paso!
Alberto: This is what happens on Earth when you mess with a man's family.
Peacemaker: Freakin' a.
Brenda: (pointing a gun) Hi. We haven't met. I'm Brenda.
Paco: (holding a stick) I'm Paco. And I'm going to hit you with this stick until you get the #&%$ off my planet.
The last moment before the Reach ship explodes, Jaime Reyes shows himself to be quite possibly the most compassionate and heroic person in the DC Universe. The ship's about to explode, Booster Gold is evacuating him, and Jaime reaches out for the Negotiator to try to get him off the ship before it explodes. This is the being who had, just a bit before, ordered the destruction of Jaime's home, with his parents and little sister in it, complete with mocking grin. No one, maybe not even Superman, would have chided him for not trying. But his instinctive reaction was to try to save the Negotiator. (Yes, he didn't because the Negotiator didn't even try to act... but Jaime tried.)
Post-Flashpoint, Jaime meets Booster Gold for the first time, who proceeds to attack him, believing that, as a holder of a scarab and an agent of the Reach, Jaime is a bloodthirsty killer. In the middle of their fight, however, when Jaime is down, Booster is smacked in the face by an old woman. The woman proceeds to tell Booster to back off, and she has an entire crowd of people backing her up, just waiting for the chance to see Booster attempt any form of physical pain on her. At which point Booster is forced to flee with his tail between his legs, spouting off some bull that the fight was all an initation for Justice League International. The woman was Jaime's grandma, and to top it off, she instantly recognized Blue Beetle as Jaime.