Gamemasters: What has been the worst humiliation your NPCs have suffered?

[Glorthindel]

I was running the Enemy Within WFRP campaign (with some heavy modification), and my party had just completed Something Rotten in Kislev. My players had endured multiple sessions of of being belittled by arrogant NPC's (they were effectively acting as foreign ambassadors, so were dealing with being snubbed, brushed off, given menial tasks to 'earn' an audience, and having people who clearly could speak their language suddenly act like they couldn't), crushing defeats, and ended it all by fleeing without enough provisions through a mountain pass in the depths of winter. By the time they made it back to 'civilisation' the characters were cold, wet, hungry, worn out, and the players had thoroughly had enough of my ****. It was glorious.

They arrive at a coaching inn in the wilds of the northern Empire; the first hot food and warm bed the characters had had in months. Enter my NPC. He was a "famed monster hunter" looking for able bodies (read: Arrogant cowardly braggard who would run off at the first sign of danger but claim the glory if the party managed to kill the beast) to hunt a Giant that was terrorising the surrounding farms. One of my players was really into his Warhammer Dwarf lore, and enjoyed going after the stereotypical monsters (he wasn't playing a Slayer, but loves the archetype), so I had kinda placed this encounter for him. But I had misjudged my players level of tolerance for being screwed around.

My party accepted the quest, trudged out the settlement with the monster hunter, then the second they got out of sight of the village, without a moment of conferring between them, clubbed him over the head, stole his weapons and trousers, and tied him to a tree with a sign hanging round his neck saying "obvious traitor", before turning around and heading back off down the road. This was possible the first and only time my players have ever done anything that could be described as murder-hobo. They were a little gutted when I told them after there really was a Giant out there, but still felt the catharsis they felt from their decision outweighed missing out on an interesting monster encounter.