Please forgive me for going all Scream on you, but you know that typical trope-moment in horror; the part where the girl trips over her own foot in a dark forest? That's not good storytelling/writing, nor is it entertaining or fun or even scary to watch. You never feel sorry for that person, you just want them to die for being such a freaking moron/klutz. It doesn't feel suspenseful, it feels like the writers just wanted the character to die at that moment, so the universe converges just to make it happen. That isn't just bad horror, that's bad storytelling in general.

The only thing the "girl tripping over herself" moments accomplish is making the audience feel frustrated.

So imagine my disappointment when they made an entire series based on this, it's called The Walking Dead. Let me start by saying I watched this show when it was new, I enjoyed the first season quite thoroughly. I thought it was fantastic, which is amazing since I normally find zombie settings quite boring. It was just so well written and the world they offered seem potentially interesting and neat. That said, I was heartbroken when I heard all the writers were being fired to hire on cheaper ones. I worried about what this could mean, and sure enough my fears were justified. Almost immediately the show became centered around the stupidity of the characters, and that one thing became the driving force moving the plot. Now, don't misunderstand me. It's perfectly fine for characters to be imperfect, and it's perfectly fine for them to make mistakes that get themselves and/or others killed. That is FINE.
The problem is 'that is the entire plot' now, and the mistakes all the characters are making are so monumentally bad they've far reached beyond stupid. It is, as I've said, now the "woman tripping in dark forest" the show! But enough of my exposition, lets see what I can remember just off the top of my head, and YOU can decide:

• Hysterical woman driving. Right off the bat the new writers make one of the more level headed characters drive off the road and get into an accident; an EMPTY road! Why? "Because she's a hysterical woman". This was pretty much the starting point for the ride I knew was coming.

• One of the characters "turns evil", and he immediately shaves his head to show how evil he is. I have no other comment.

• Zero supervision for children: a common theme that is going to get people killed repeatedly from this point on. The child of the main character is allowed to wander out by himself in this zombie infested wasteland, and of course he brings back a zombie to the farm everyone is bunking at. When they kill it the sound alerts all the other zombies in the area, and sure enough everyone is screwed.

• Walking into a dark hallway filled with motionless bodies, because what could be better then walking over potential zombies in a dark, cramped place with no escape? When they find the prison, their first instinct is to clear it out, so they go from room to room. They go into this dark hallway, stepping over bodies like the most freaking stupid people in all existence, until (shock!) they start moving and the old man gets bit in the leg. This was truly one of the most aggravating scenes in the entire series, I couldn't stop wincing.

• Woman runs through forest, escaping badguy. She arrives at a clearing where she can see the prison (where the good guys are) only to STOP FOR A WHILE AND SMILE WITH HER BACK TURNED TO THE FOREST. As she paused there I just winced and convulsed while mentally head-desking a million times. I won't spoil what happens (I don't have to) but I just wanted her to die form that point on. When she did it was very relieving.

• Farming next to a rickety fence being pushed on by zombies... WHILE PURPOSELY WEARING HEADPHONES.

• Not expecting anyone to die suddenly in the night. The way The Walking Dead world works is everyone is infected, so when anyone dies for any reason, they turn into a zombie. While the main characters hold up in a prison with a bunch of other families, they focus any security to the outside of the building, expecting thugs or zombies to attack. Apparently, it NEVER crossed anyone's mind that someone might just die in the prison from natural causes ...Am I seriously expect to believe this!? For Christ's sake, someone may fall down some stairs or slip and break their neck while peeing. But no, NO ONE thought of this apparently, and guess what happens...

• Girl and hillbilly escape the fall of the Prison, he shows large signs of mental instability so she purposely tries to get him drunk. She purposely... tries to get him drunk. SHE PURPOSELY TRIES TO GET HIM DRUNK. What is sense? Putting aside what a mess the guy is (and the obvious dangerous-drunk he turned out to be) it's just them... Zombies are everywhere and you want to get drunk without anyone being level headed enough to do anything!? What - in - the - HOLY - CRAP.

• Little girl proves to be mentally unstable and even dangerous. Adults leave her alone with her younger sister and a baby; even allows them to play outside with zombies everywhere, with the baby. Arms them... WITH THE BABY. Somehow, by some weird inconceivable coincidence, leaving two younger kids with a crazy older kid (who recently tried to feed themselves to zombies) turns out to be a bad idea. Truly strange how that worked out, if only someone could have seen this coming. I feel so bad for these character, truly all their hardships are just a run of terrible, terrible luck that they don't deserve. Yes, truly.

I am sorry, are the characters just supposed to be so freaking stupid they're completely unlikable, or are the writers just this bad at understanding how actual interactions and 'thought' works? I mean, I don't expect everyone to be "badass survivalists", but for Christ's sake, if NONE of the characters have once ounce of common sense or even a little will to survive, it's really hard care about what happens to them. If this was a one-shot horror movie who's purpose was to kill off everyone or gross-out, it would be fine because it's short and then it's over. But The Walking Dead is a god damn series that's 95% character development and 5% plot. The characters are supposed to be important, they're the focal point. This is just so poorly done it's freaking astonishing.

tl;dr
How not to write Horror: Don't make the characters do things that make the audience cringe, otherwise it's not longer "horrible" when those characters die.