Dungeon Masters carefully curate the gameplay for their beloved parties.
Aware of their barbarian's weakness for dragon-slaying and the wizard's affliction for casting fireball every chance he gets, they often will cater their storyline to the needs of their friends. They'll kneecap the cave-dwelling knight cults' strengths and hinder the swamp witch's full power at the fork in the road because they want their party to have fun and carry on with gameplay.
However, no DM can claim they don't feel a certain level of pride when they score a TPK. Secretly (and sometimes not-so-secretly), every DM relishes the supreme power of destroying their friends, darkening the room to a magical darkness that withstands Dark Vision and summoning gargoyle hoards of biblical proportions. As they flex their mighty imaginations and lull their party into uncertain waters, the mega Dungeon Master unleashes a multi-roll beast that no party could destroy. Alas, the game night may be cut short, but everyone's going to go down swinging.
When in doubt, a foolish wizard casts Fireball in a small, enclosed room, engulfing the entire party in flames. Sometimes a TPK is a little easier if you've got a party that engages in total buffoonery on a regular basis…
