...and I mean Joss, not Will.
You see, if you ever watch anything that Joss Whedon ever produces, you'll learn one simple nasty little tick to drama: Let everything seem to be right in Rightsville, then murder, rape, and burn Rightsville in any and every manner you see fit.
The way this applies to D&D is, if your players have a person, place, or thing that they love, fucking destroy it. Shit on their hopes and dreams.
This should only be done sparingly, however. If it happens even once too often, you'll end up crushing the character's spirits. Your PC's will stop building castles after the fifth one burns down and sinks into the swamp.
During last night's game I did this.
The player's had just finished an adventure, gotten paid, won fame, and uncovered the location of ancient secret power. So, as they were sleeping off the effects of their revelry, a volley of catapults began destroying everything they ever loved in advance of a complete sacking of their city by foreign invaders.
They were forced to flee into the orc-controlled woodlands to the north.
The fires of doom warm my DM's heart.