The scene in which Daryl was forced to kill Merle simply has to make the ranking because it was such a devastating moment for everyone. Although many viewers were happy to see Merle die, it was at the same time painful watching Daryl fall to the ground weeping for having been forced to kill his own brother. The killing happened in season three of the series when Merle had gone all in force towards a Walker. It is definitely a scene one will never forget.
