After The Walking Dead Season 7 premiere, Jeffrey Dean Morgan explains why Negan did what he did to Rick.

Warning: Spoiler material for The Walking Dead Season 7 premiere, “The Day Will Come When You Won’t Be.”
While The Walking Dead took flak for its cliffhanger stunt, the Sunday Season 7 premiere virtually tied its all-time high with 17 million viewers, giving the show's producers and network AMC the validation they have waiting to receive. However, amongst the brutal, emotionally gripping results, was the long-drawn, torturous approach that Jeffrey Dean Morgan’s Negan took with Rick (Andrew Lincoln), rather than just killing him. Now, the actor explains why.
In an official behind-the-scenes featurette, Jeffrey Dean Morgan explains the motivation of his barbed-wire-bat-wielding zombie apocalypse extortionist in Negan. While the Season 7 premiere showed Negan head-bashing a defiant Abraham, who managed to turn “Suck my nuts” into famous last words, he also – in comic-adherent fashion – executed Glenn as punishment for a defiant outburst from Daryl. Yet, much of the episode focused on a vindictive one-on-one dynamic as Negan exercised duress over Rick, subjecting him to apparent litmus test tasks gauging his willingness to cooperate. As Morgan explains of Negan’s process:
“You would think that killing two of his people would’ve done it, but it didn’t. Rick was holding on and Negan wasn’t gonna let that happen.” Adding: “Maybe the smart thing would’ve been to kill Rick, cut the head off the snake. But, I think Negan is thinking a couple steps ahead here. He’s like, ‘well, wait, if I can break this guy and have him working for me, I stand to gain a hell of a lot more.”
Indeed, Negan himself explicitly explained in the Season 6 finale that he wants Rick’s group to live so that they can keep gathering supplies to give to him. Thus, he limited the executions of Rick’s group, merely using them as extreme examples of what non-cooperation will yield. Yet, a shocked Rick remained defiant; something that Negan senses, which leads to a move that ultimately breaks the alpha spirit of Rick when he’s seemingly forced to use his “axe” to chop off Carl’s left arm under threat of everyone’s execution. After it was clear that Rick was broken, Negan nixed the arm-chop request. As Morgan explains of that moment:
“As horrible as the death of two of his survivors, that moment of the possibility of cutting off Carl’s arm I think is the emotional low point of the show. I think it all led to that.”
Thus, the methodical pace of the premiere with the Negan/Rick dynamic was designed to deconstruct the wall of confidence and recalcitrance that Rick had built after seven seasons of death-defying escapes, even from situations resembling their current predicament. Andrew Lincoln himself even implies in the featurette that the episode was about Negan’s process of leaving Rick “emasculated,” or, as Negan’s famously lewd comic book line states of the dynamic he’s aiming to achieve, “I’m gonna slide my d**k down your throat and you’re gonna thank me.”
Consequently, much of, if not all of Season 7 will likely be devoted to Rick finding his way back from that experience. That process will commence when the survivors slowly pick themselves up in the aftermath of the premiere tragedies and meet some new possible allies in the coming fight.
The Walking Dead continues a prospectively devastating Season 7 on AMC on Sunday nights.