keeveek: This really depends on a show.
Now I remember that some TV series got it right, by intentionally restricting the show to only a certain number of episodes, even without further seasons.
Those TV series feel like movies which are just divided into several sections. They still have a meaningful end, and it always feels the whole series is aiming to that climax, and not just dragging it out to fill episodes.
I think "Rome" was a good example (it had two seasons, but it always felt to me the whole story was mostly thought out fully already when they started shooting the first season), and I also recall certain British TV series from the late 80s or so where two agents were trying to find something about some hazy dealings with an UK nuclear station or something, and the protagonist (agent) kept being haunted by his dead daughter who had been some kind of activist dealing with the same nuclear station, and died while doing that.
timppu: like that the zombies do eventually die of hunger, if they really get nothing to eat for a very long time), but those Walking Dead zombies... meh.
keeveek: This actually makes it more stupid than less, becuase that would mean entire digestive system of zombies work, so zombies eat, digest and poop like normal people.
Still, it worked for me in e.g. 28 Days Later (IIRC). I think they have to put a limit to somewhere, like those separated zombie heads in Walking Dead which apparently keep making noises forever. Well, if it was a supernatural show, but Walking Dead already made the mistake of giving it sort of scientific explanation during the first season, I think.
But I guess it is part of the drama that if you become a zombie, you would be eternally just doing something (even if you were a mere head anymore), until someone puts a hole into your head.
Anyways...