Most Offensive Part
The most offensive part was at the end with Christian Stereotype #2 saying "it's a miracle he's been healed" or whatever, then Paul tells his buddy "you can't live with these people."
THAT'S NOT A JOKE! There was no punchline there. No humor. Just an angry writer screaming on the page. The rest of the movie was common stereotyping, the atheist equivalent to black face, but that line was particularly poorly conceived. Anger controlled can be a good tool for comedy, but if it's unrestrained it'll only appeal to other people angry at the same thing. It's like playing Birth of a Nation at a clan rally.
Also, why did Hader's character all of a sudden become so evil? And why was Christian Stereotype #2 hanging out with the gang at the end, even though he'd just murdered someone?
I loved parts of this movie but it could have used a re-write.