Inspired by Why doesn't Buzz know he's a toy?, Buzz Lightyear believed his toy backstory was that he was a a space ranger out to defeat Emperor Zurg, as described on the back of his box. The short film Toy Story that Time Forgot showed the Battlesaurs were similarly aware of, and believed in, their fictional backstory.
We find out in Toy Story 2 that Woody also had a fictional backstory in the show Woody's Roundup. However, Woody is completely unaware of this and doesn't recognize the other characters from his backstory: Jessie, Bullseye, and The Prospector. This seems very odd to me, as Buzz Lightyear knew his backstory, and recognized Emperor Zurg on sight (and the Battlesaurs did the same with their supposed enemies).
So why was Woody unaware of his toy backstory when Buzz knew his?