In the Toy Story series, the feisty Jessie is prone to excitability in more ways that one, given to hysterical panic attacks after years of being left in a dark box. Now, thanks to a newly-posited theory on the character's origins, we may finally know who's responsible for all her abandonment issues, claustrophobic conditions, and anxiety. As is usual with such things, she can blame mom.
Jon Negroni (via), who previously put forth a unified theory of Pixar chronology, has put forth a far less ambitious, more conceivable notion regarding the Pixar universe: what if Andy's mom is Emily, the little girl who outgrew Jessie?
The full theory is outlined here, and there's some pretty decent evidence that goes well beyond a generic, inherited affinity-turned-rejection for cowboy effigies. In the films, Andy is seen wearing a cowboy hat, but upon examination, it's clearly not a replica of Woody's. Just a random cowboy hat taken from one of Andy's many cowboy victims then? So you might think! Except that his hat actually does have match in Jessie's, save that where hers has a white band, his has a faded area where a band seem to have been before.
Now, have a look at the glimpse of Emily's room given in Jessie's origin story. Hey, there's that hat on the bed--though, in later scenes, it's not part of the donation box of toys Emily gets rid of. So: maybe Emily kept the hat, later giving it to her son, who, in a twist of fate, would later end up getting the very same donated Jessie back. It's not exactly a bulletproof argument, but it's also pretty fathomable given Pixar's penchant for Easter eggs and Andy's mom's cruel disregard for old toys. Sure, it's at least equally fathomable that Jessie hats were merely the novelty article owned by pretty much every kid of the time--the Hulk gloves of another era--but as Negroni points out, do you want to believe, or "do you hate fun, love, and destiny?"