Nothing gives the viewer an emotional jolt quite like the sudden death of a well liked character. As long as these moments are done with some emotional resonance, and not just for the sake of shock value, these scenes can become the highlight moments of their respective shows. The most gut wrenching scenes of Breaking Bad or The Walking Dead, for example, have to do with the loss of a favourite character.
Of course the downside is that the character is supposedly gone for good, outside of a flashback or dream sequence. That's unless viewers keep complaining or the show desperately needs to drum up ratings, in which case a dead character can find themselves with a new lease on life.
The most enjoyable aspect of these miraculous comebacks is just how stupid will the explanation be? Often the characters were killed off in a very definitive way, and the poor writers have to jump through some ridiculous hoops to make their resurrections seem credible. And more often than not they’ll fail, as most of the examples here will show. It's a bad sign that a year long shower is one of the more credible explanations on offer.
And just be warned folks that generous SPOILERS lie within.