Me: *stabs vampire*
Wife: omg
Me: *beats vampire to death*
Wife: OMG
Me: What?
Wife: You're supposed to give them candy!
Me: Well, that's a sticky situation now, isn't it, Barbara?
Me: *stabs vampire*
Wife: omg
Me: *beats vampire to death*
Wife: OMG
Me: What?
Wife: You're supposed to give them candy!
Me: Well, that's a sticky situation now, isn't it, Barbara?
The humor comes from the classic Halloween tradition of giving candy to trick-or-treaters, specifically vampires. The person in the story completely misses that and instead attacks the vampire. The wife is shocked and points out the obvious social expectation. It's funny because of the mismatch between expectation and action.
Anonymous
XDDDDDD