Over the course of The Walking Dead's zombie apocalypse, Rick Grimes has been through multiple highs and lows, but his biggest decision with Negan proves to be his greatest success in the series' final moments. Rick's band of survivors might have encountered some pretty tense moments against zombie hoards, but their greatest enemies turned out to be just ordinary people like The Governor and the Whisperers. However, the most notorious villain of the entire series was Negan.
Armed with a baseball bat wrapped in barbed wire, Negan became one of the most iconic villains in the comics. He was remorseless and brutal as he ruled his group of survivors, The Saviors, with an iron fist. His introduction to Rick's group is also infamous as Negan brutally murders fan-favorite character Glenn Morgan, sparking an all-out war between them. This is a character that has become a popular villain among fans, and when Rick finally had the upper hand over him at the end of the war, his decision to keep Negan locked up in jail instead of killing him was a surprising one seeing how he vowed to kill Negan after Glenn's death...but this decision was for the best.
Left with nothing more to do than see Rick's society flourish, Negan claims to have changed throughout the rest of the series. This is a man that has done terrible things and was surprisingly spared. However, he comes to admit that his murderous behavior was a byproduct of years of internal trauma. After his wife, Lucille, passed; he was unable to truly mourn her due to the rapid decline of society and the need to survive. This led to him shutting off his emotions from the rest of the world, turning him into the cold-hearted leader that readers were first introduced to in the comics. Spending time locked up in prison gave him the time he needed to reflect on what he's done and mourn his wife...and the results speak for themselves in The Walking Dead's final time jump forward.
Negan can be seen laying flowers at Lucille's makeshift grave. For years, he would only channel her through his infamous bat as a way to keep authority among the Saviors. Now, he's finally taken the time to mourn and put her memory at peace. Years of self-reflection while behind bars and looking into his emotions have changed Negan and helped him realize that Rick's views on society are the right way. An emphasis on hope to help things go back to the way they were is something he never would have accepted if he continued to do things his way and would probably have gone to the grave with him if Rick had killed him but taking the time to show him how Rick's vision helps shape the rebuilding of the world is enough to change him. This ending for Negan was so fitting, The Walking Dead's T.V. adaption is hinting at it now.
Rick has succeeded and failed multiple times throughout The Walking Dead's run. From building up hope for his group to losing members, he's certainly been through a lot in the direst trials humanity has ever faced. However, his change of heart to not kill Negan easily led to his biggest success. While it seemed pretty improbable in the short term after everything he had done, the end result of his choice led to one of the most vicious antagonists becoming a believer in Rick's message. Negan is the success story of the century because of Rick Grimes' choice, and his lifelong change in character is enough to show that even in the darkest moments of The Walking Dead, hope can bring anyone to the light.