One thing I don't get (spoilers)
Why was this gonna be their last Christmas?
I get that Seth Rogan was becoming a father and Anthony Mackie was "famous" but that side plot almost didn't seem necessary. Rogan's wife was like really cool letting him hang out with his friends even going as far as to give him drugs. I feel like she woulda been fine letting Levitt hang out for Christmas every year (which in the end winds up happening,)
I feel like it was more their last Christmas to Party Hard. That's what it seemed more about to me.