I found plenty of "joy" in UP. This movie really made me reflect on my own life. I left the theatre feeling so much love for my DH and children. As Russell said, "The funny thing is, it's the boring stuff I miss the most." Made me really appreciate the quiet times with DH, sitting and drinking coffee in the morning, watching the kids play in the backyard. When Carl found the pictures in the book that Ellie left as her adventure, I could see my own life in them. I left with joy in my heart.
As far as finding the pictures in the book being unrealistic, I could see Carl not looking at the book because it is too painful. Since they could not go on any "adventures" during her life, he probably did not want to look at the book, as it reminded him of unfufilled dreams. Anyways, I bought into it and I am usually very cynical at movies.