yes, yes, yes. Sadness is essential -- Joy (like R's parents) won't let Sadness touch the memories and be part of R's experience. Joy first starts to get it when Sadness listens to the imaginary friend's feelings (I think) -- and the imaginary friend feels better. This is reflected with the parents when R finally expresses her feelings to her parents and they say that they feel sad too and miss Minnesota too. R doesn't have to carry her sadness around by herself. At the end we see Joy handing the core memories to Sadness and each memory changes colour somewhat. Each memory is tinged with sadness, as our memories are in life, because they are past. Joys and sorrows both. caeli says it well also -- emotions and memories become more complex and nuanced as we grow up. Empathy includes letting another person feel her feelings and work through them: "Cry if you want to/I won't tell you not to/I won't try to cheer you up/ I'll just be here if you want me/to be/near you."