9. Booster loses his sister and decides to troll Superman (and Luthor.)
Booster Gold #23 Vol 1. This one I'm picking just because of how entertaining I found it. Booster acting like a jerk to his rivals--who kinda deserve it. I'm not counting the whole arc about Michelle dying because there really wasn't much mention of her until the second BG series. Still her loss marks the beginning of the end of this chapter of Boosters' life. It also gives him an excuse to mess with Superman and Lex Luthor. Literally hearing about Superman fighting a Booster-look alike after his sisters' funeral he saves his rivals life from the robotic double. Then gloats about it by waving a stray piece of kryptonite in front of Supermans' furious face.
Later on Booster decides to crash Lex Luthors' party to tell him that he knows (though can't prove since the evidence was destroyed) the robot was created by Luthor. See the two of them were at odds in the business field at the time and Luthor truly saw Booster as a threat he needed to crush. Booster tells him that the company they were fighting over, the one LL bought, was a ruse. Because Booster never wanted it since his information says the company will take a big dive very soon. Then he decides to one up Luthor again by whispering something into his (Luthor) dates' ear. Smiling she asks who's place their going to abandoning Luthor. Booster gives one last parting shot saying that next time Luthor wants to create a robot he better make a female one. Ouch.
Edit: Actually this is even funnier on highsight since Luthor DID make a female robot (a Lois look alike.)