You've been in a great adventure, things are looking up, your character has made it past level 1, level 2 and finally made it into level 3, where he is a bit more stable. Suddenly the DM is throwing different monsters at you, the rewards are getting bigger and you decide that its time to take a few more risks.
One by one your party members start dropping like flies, and finally its just your character left. So you decide to run, the monsters give chase and finally corner your character due to a wrong frantic turn. You decide to fight for your very last breath...
*FADE TO BLACK*
The group all throws their hands up in the air as the last character finally drops down to the ground dead, screaming at each other with blames, and then finally turn to the DM, blaming him for being so cruel.
Is it the DM's fault?
Was it the Party's fault?
I think it can be a mix of both sides for the correct answer.
Face it, a TPK is memorable, but in the long run is not really all that fun (except for the DM).
In this very situation, the party could have decided to not skip those rest periods and be "XP greedy" as I've heard some people call it. Maybe if they rested properly they could have survived what seemed like an easy encounter.
Maybe the DM should have not had the monsters pursue the character that attempted to run away from the monsters.
But doesn't the DM have the right to play the monsters as he sees fit?