I won't tell you my favorite parts, because I don't want to spoil it for you.
What I will tell you is this:
The beginning of the movie and the end are amazingly funny and on the nose with their sarcastic viewpoint about how we all relate and communicate.
However the middle, where Joy and Sadness have to find their way back to headquarters, draaaaaaaagggggggeeeed on FOREVER. I know they had to make the move a certain length, but the middle section had hardly anything that kept the adults engaged.
HOWEVER, that being said, the movie is NOT for adults. The target market, your kids, will love it! My kid, at 12, was probably the oldest there, and he thought the entire thing was awesome.
He even said, "I'd see that one again." That is rare - especially coming from someone, who thinks most things are boring unless they're video game related.
So my middle drag out boring hum drum portion that I'd tell you to bring a pillow for, was still a home run for the kiddos.