The writers ruined Piper's character in the second half of the season. She started S3 admitting she got Alex back in prison for selfish reasons (she missed her), asking her to be her girlfriend and telling her parents that she had a girlfriend that she loved. I thought great, she's finally being who she wants to be, instead of who her parents and friends expect her to.
But then the writers went over the top and turned her into something she never was. I mean, she has always been selfish and entitled, but I had never thought of her as a bad person. First, she mocked Alex's fear of being attacked (which was completely justified) and cheated on her with a girl she barely knew (not the same as cheating on Larry with Alex). Then, she became the caricature of a villain. Feeling good about having the poor girls under her thumb. What she did to Stella was straight up unforgivable. That girl is being sent to max with an extended sentence. She could get beaten up, raped or even killed there. I don't see how Piper can fix what she did. Neither can I see how the writers can fix what they did to Piper's character. "Sorry" certainly doesn't cut it.
This should have been the story of a privileged white woman who went to prison and -through the interaction with people she would have never met in her regular life- got a much needed dose of reality and became less self-absorbed. The writers decided to turn her into a Walter White wanna-be instead.