I normally LOVE Pixar movies. They know how to take a great story and bring it to life. Not the case this time.
I learned long ago when you try to make everyone happy you'll never make anyone happy. When dealing with death and the afterlife you need to take a position; believe in something. This movie falls flat when it tries to explain the reason for your existence. It will vary, based on what you believe.
The WORST part is to imagine your soul on a giant conveyer belt heading toward an enormous Bug Zapper...what?!?!! Hide the children; nightmares for days.
Because Disney tries to validate so many beliefs it satisfies none. My daughter's said, "I expected to cry". Didn't happen. Why? Because the plot got lost and left us feeling the same way.
Compare this to the final scene from "It's A Wonderful Life". People rushed to George's aid because they shared a common belief and purpose. That moves us. Unfortunately, Soul didn't.