When I achieve a TPK, I feel I have completed my job as a DM. Or at least, my secondary DM goal.
The way I see it, it's you versus the players. Obviously events are stacked mightily in your favor since you are, you know, GOD, but if you operate within certain limitations and then play the monsters/NPC's/villains out the way they should be played, and the end result is the TPK, congratulations.
You just outsmarted and out-played all of the PC's combined. As long as the match up is even, I will take satisfaction from the TPK. If I did, either by mistake or judgement or mistake of numbers/abilities/CR/etc I'll actually feel guilty for it.
Ultimately the question isn't whether or not you anticipate TPK's, it's whether or not they're fair.
As a player, I won't get uppity when my character dies by himself, or in a TPK; as long as we had a fair chance of survival/victory. If the match up was something along the lines of a 2nd level party going head to head with a Balor, there would be major screaming on my part at the DM, promptly followed by a real-life mimicry of what the Balor did to the PC's. ~.^