Mr. Potato Head was Andy's favorite toy before Woody:
He knows that Woody was "Andy's favorite since kindergarten", meaning he was there at the time. He's also the only one in the room that seems to not have any respect for Woody, while the other toys respect him and treat him as an unofficial leader, possibly from some bitterness due to Woody replacing him as Andy's favorite. Andy is a filmmaking major:
Every time we see Andy playing with the toys he’s able to improvise original stories where there’s always a place for every character. There’s no reason he wouldn’t use that creativity in college. His sentimental attachment to his toys even as he’s ready to start adulthood shows that they probably played a big part in creating his lifelong passion.