"Why'd They Do That?"

As a storyteller, have you ever found yourself forced to make... odd storytelling decisions in order to support a twist of the plot later on?  ("How can I explain Don's surprising prowess at spinning pizzas in the climatic pizza-making championship?  I know, let's give him a life-long interest in pottery wheels!")  Well, bless you if you haven't, because I certainly have.

I suspect this sort of wrangling happens pretty often, actually.  "Why'd They Do That?" will be a series of blog posts where I take an example (more precisely: something that I think is an example) of a strange story choice, and then attempt to explain it away with keen insight (by which I mean wholesale guessing).