In the movie Inside Out, there comes a times towards the end when the emotion Joy (voiced by Amy Poehler) and Riley's imaginary friend Bing Bong (voiced by Richard Kind) fall into the memory dump.
Memory Dump is the place where memories evaporate away into non-existence. As Bing Bong and Joy try to use Bing Bong's wagon to fly back to higher grounds, we see that Bing Bong is slowly but steadily evaporating away i.e. he's being forgotten as well.
So why is it that Joy is intact and not fading away like everything in memory dump is?