When you find out why Claudette is in prison. She killed the man who was abusing the girl who worked as his maid.
Following her unfair stint in solitary confinement (during Fucksgiving, season 1, episode 9) thanks to jealous prison guard Healy and manipulative hick Pennsatucky, a determined Piper heads straight for her ex-girlfriend Alex and leads her away into the chapel. Once there, the two finally relieve some of their obvious Unresolved Sexual Tension since reuniting at the end of the pilot episode. Also may count as a Big Damn Kiss moment.
In the same episode, Piper's epic speech to Healy from her cell.
When the prisoners meet the juvenile girls, Suzanne quotes Shakespeare at them. It's amazing and terrifying.
Piper scaring a girl straight without acting, exaggerating, or threatening her. All she does is give an honest, disturbingly calm assessment of what prison can do to your emotional well-being and sense of self-worth, and it's enough to render not just the girl she's talking to but all the other students, inmates, and staff members in the vicinity completely speechless.
Chapman: I'm like you Deana. I'm weak too. I can't get through this without somebody to touch, without somebody to love. Is that because sex numbs the pain, or because I'm an evil fuckmonster, I don't know. But what I do know, I was somebody before I came in here. I was somebody with a life that I chose for myself. And now? Now it's just about getting through the day without crying. And I'm scared. I'm still scared. I'm scared that I'm not myself in here, and I'm scared that I am. Other people aren't the scariest part of prison, Deana. It's coming face to face with who you really are. Because once you're behind these walls, there's nowhere to run, even if you could. The truth catches up with you in here, Deana, and it's the truth that's gonna make you her bitch.
Washington: Damn, you cold.
Chapman: Bitches got to learn.
Sophia not bowing to Pornstache's attempts to extort her into sex for her hormones, despite the personal hell waiting for her when she goes through withdrawal and then a complete lack of hormones.
In the season 1 finale when finally getting dumped by both Larry and Alex (her fiance and girlfriend, respectively), ostracized by almost every other prisoner, then backed into a corner by an armed Pennsatucky before eventually getting ignored and left to die by a vindictive Healy, a desperate Piper snaps on her Knight Templar nemesis, who'd been planning to kill her for the last several episodes. The resulting No-Holds-Barred Beatdown is truly an epic sight to behold.
Piper ends up sharing a cubicle with Claudette, one of the oldest convicts there who is extremely strict about the conduct of her roommates. After having a bad day, Piper finally tells her to lay off. She launches into a tirade about all of the things she's had to deal with since coming to prison, and asks her to cut her some slack. As she walks off, Claudette slowly smiles to herself.
In 'Tit Punch', even though it landed her in jail, Red punching the woman who made fun of her in her breast implant.
After several occasions when a (sometimes well-meaning) Alex screwed Piper over, Piper finally gets a pretty twisted revenge: she gets a freed Alex thrown back into prison with her. On the one hand, this is very decent revenge for Alex coercing Piper into perjuring herself while Alex made a deal and was set free, and on the other hand, Piper can justify it by claiming that she was saving Alex's life by getting her out of reach from a man who wanted her dead, which is in fact true. It's deliciously messed up and should quite an interesting dynamic going forward.
Adding to the CMOA is that Piper enlists Polly and Larry into getting Alex thrown back into prison. Larry rightly guesses that part of Piper's motivation is to get Alex back in with her, and it's not quite a reconciliation between them, but Piper points out that it gives them a chance to screw over someone they don't like.
Cal and Neri's surprise wedding. The sincerity in their relationship is a clear contrast to the lack of it in any of Piper's.
Piper's verbal beatdown of Polly and Larry pretty much said what some of the audience was thinking at that moment.
On the other hand, Polly's deflection reflects an already-twisted message of the show: that we can't choose who we love and it just sort of happens (which, as we've already been shown, is true for Piper and Alex). And her vagina ''did'' bounce back.
Healy's forged paperwork that "proves" what he knows to be true: Suzanne was not responsible for Red's beating.
Morello cursing Vee to her face;
Morello: "May you never have a minute a' peace."
Taystee, Poussey, Janae and Cindy all turning on Vee, berating her and letting her know that she's now in a prison full of people out to get her, with no one to back her up.
Black Cindy: We about to recant our shit.
The Karmic Death of Arturo, Gloria's abusive boyfriend, who's trapped in a room after he knocks over a candle and is burned to death.
Rosa's final escape, especially when she makes roadkill out of Vee.