9. Charlie Pace - Lost
Rock star drug addict Charlie Pace (Dominic Monaghan) is undeniably one of Lost's all-time fan favourite characters, so a good portion of viewers were left utterly distraught when he suffered a sacrificial drowning death at the end of the show's third season.
Charlie was in many ways Lost's heart and soul, because watching him grow and conquer his demons over the course of those first three seasons was simply enormously gratifying to watch.
And though Charlie certainly met a fittingly heroic end, his absence nevertheless left a void for the remaining three seasons and near-50 episodes.
As a slight consolation to fans, however, he did at least make a few additional appearances, both as a vision and in the show's "flash-sideways" sequences.
Even so, one can't help but think his death might've been even more of an emotional sledgehammer had it occurred a little later in the show's run.