A Darker Version of the Original, Toy Story 3 is a Sequel to Toy Story 2.
The first Toy Story was intended to introduce a character that was far darker than the characters in the sequels. The character of Woody wasn’t always the kind and easy-going toy that he is now, especially early in the story.
As a last resort, he was prepared to toss Buzz out of a window if that was the only alternative. Pixar regained creative control over the story, resulting in a less traumatic experience for the audience overall.