Here’s just a couple I’ve come by.
Lack of characters. The one thing a show cannot live without. If there’s no one to care for – and even agent Ward was not hopeless – why bother watching at all?
Lack of script. I admit, this has more to do with crime shows than with regular teenage and/or sci-fi stuff I watch (I know, I’m pathetic), but it’s even a bigger problem with, say, Teen Wolf. Or Glee. Wait, are we talking script or continuity? You had me for a moment there…
Lack of Bechdel passable scenes. Although I have been known to occasionally watch a show or two which break this rule (most notably Grimm), I still think it’s a thing to take into account. Even if it’s only Castle’s Beckett and Lanie talking over a dead female corpse.
Lack of future. If you honestly don’t care about the next episode… I figure many of the problems in this area can be traced back to Moffat. Or attributed to him. Who cares if he’s really to blame? Oh, and then there was Firefly. But I guess no one could’ve known.