You're supposed to be upset.
See, I'm one of the people who is mad, but I KNOW I will be watching the spoilers and tuning in to the premiere, because I feel disgustingly obligated to see where they take this show, for better or worse. That said, I do not subscribe to the meta explanations given by the producers "oh you're just feeling the anguish the characters do", "it'll all make sense", "this scene is the end of one arc, and the
death is the start of another". That is NOT effective storytelling. If we were supposed to be in the mind set of Rick's group, then we should have seen every single hit, unable to escape it, unable to change it, and finally forced to accept the death of our friend/family member. The crushing helplessness of that scene is one of the most important moments in the books, and shows that they are truly living within a new world order. The cliffhanger is cheap, lazy, and makes people mad for all the wrong reasons. We should hate Negan for taking away our friend, and then walking away so casually. Instead we hate Gimple, or Nicotero, or AMC, because they neutered this moment, and effectively called loyal fans of both mediums "whiners" or "crybabies", for wanting a payoff we had been promised for months. The finale had a great amount of tension, so much so that we were willing to forgive the fact that they quite literally drove around in an RV for the greater part of a 90 minute episode, but all of that tension was thrown straight in the garbage when those credits rolled.