Yeah, really.

I can live with a few NPC's being essential, for truly critical quests. But if a quest is relatively minor, you should be able to kill the person involved, and then get a QUEST FAILED alert. That way, if you want to do the quest you can reload, and if you don't, screw it.

Well... I want to break quests. I want to reload and learn from my mistakes. Let the game laugh at my silly newbie mistakes instead of preventing them. I'll learn eventually, one way or another. Maybe that's just me... and it's just that sometimes I simply want to kill an NPC, but the damn essential tag doesn't let me.

I had that problem in Markrath.. With many people.. Many many.. Pissing me off, but being unkillable.