The Walking Dead currently has Daryl in a dark place and Norman Reedus explains his motivations.

Warning: Spoilers for The Walking Dead Season 7 episode "The Cell."
A few weeks back, after The Walking Dead aired its shocking Season 7 premiere, Norman Reedus teased a “very, very dark” future for Daryl after accidentally causing the execution of Glenn by Negan and subsequently being whisked away as a hostage. Yet, with the latest episode “The Cell,” it turns out that Reedus was being quite literal in his description. While it served as an introduction to life on the Saviors’ home base of Sanctuary, the episode was also an agony-inducing marathon montage for Daryl fans as their revered redneck idol was continually tortured. Now, Reedus explains Daryl’s motivation in enduring this process.
Reedus spoke to multiple media outlets about the instant classic of an episode in which a naked Daryl was thrown into a dank, dark room while being tortured with a constantly-playing upbeat tune, forced to endure the squalid conditions and daily visits from Dwight (Austin Amelio), who delivered mockery and dog food sandwiches. Yet, for Daryl, the real torture was his own personal guilt over getting Glenn, his friend since the show’s beginning, killed in a brutal manner. However, it’s a scheme by Negan to break Daryl down and recruit him with the simple concession of saying – like everyone else does – “I’m Negan.” As Reedus explains to THR:
“He's letting it all happen. He thinks he deserves to be there, and he thinks whatever the Saviors throw at him, he thinks he deserves it. He's not fighting back at all. He's lost the will to fight. That's why he won't say that he's Negan. It's such a "f— you!"/"Yeah!" moment. You want it to feel like it's the last thing he has left. It can't look like it's a middle finger. It has to look like Daryl is feeling like his humanity is the last thing that he has.”
Daryl’s dire straits aside, the underlying theme centered on the parallel paths of Daryl and Dwight, who each made their choices when it came to Negan that yielded radically different results that could have converged, had Daryl cooperated. Consequently, Dwight – who Daryl met and helped last season with bad results – is attempting to validate his own regretful choice of bowing down to Negan. While Dwight's choice – an apparently selfless act – has given him a high status with the Saviors, it was also an emasculating one that cost him his wife Sherry and resulted in his face being burned with Negan’s iron. Yet, for Daryl, his own selfless motivation is the reason he can’t capitulate. As Reedus further states to THR:
“Daryl can't do it because of the same reason that Dwight did things that were sh**ty because he had something he was protecting. Daryl can't say, "I'm Negan," because he would be giving up what Glenn was to him and what he was to all of the group. Glenn was the heart of our group; he was the optimist and he believed in people. If Daryl was to say, "I am Negan," he would be disrespecting the memory of Glenn. And that's why Daryl can't do it."
However, lest anyone think that everyone’s favorite world-wrecking zombie apocalypse ass-kicker Daryl Dixon has resigned himself to either self-loathing torture or a putrid existence as a walker impaled on a pole in the Saviors' yard, think again. When asked if Daryl has given up, Reedus tells EW of his character’s enduring resolve:
“No, Daryl’s a fighter. He fights to the end, but in saying out loud his name instead of Negan’s name — it’s the last shred of himself that he has and for his friends. I assume he thinks he’s going to get killed right there when he says he’s not Negan. He’s signing up for more torture, but he’s doing it for the love of his friend.”
While the prospect of more rounds of torture or possibly death doesn’t sound like an auspicious future for Daryl, it does appear that Negan is intrigued by him and might just keep him around long enough for an opportune moment to be unleashed from his imprisonment. In the meantime, Daryl is still stuck in that “very, very dark” place, tortured not only by the Saviors and their sickeningly sanguine music (“Easy Street” by The Collapsable Hearts Club), but with the his own guilt over Glenn’s death; something that got a lot harder to endure when Dwight sadistically slipped him a Polaroid of his friend’s head-bashed remains.
The Walking Dead continues an extremely difficult Season 7 on AMC on Sunday nights.