Religion: What's the worst that can happen?

The bad that comes out of any religion certainly is still a child, a result of that religion. I mean, it’s not like the people who do “bad” things in the name of their religion are doing it because they feel it’s wrong.. they do it because they believe it is right. They do it because their religion’s views/complexity/ignorance allow for someone to be so “misguided”... really, for all we know, maybe the “bad” people are the only ones who have their religious interpretations “right” and all the others are just too lazy or not faithful enough to take the drastic steps that the “extremists” do.

- General Christianity at it’s worst was the Dark Ages, honorable mention to Hitler and his neo-nazi fans. Nowadays, the worst Christianity has to offer is what?.. failed science education in schools, i guess…
– The Jewish faith at it’s worst is…?
– Scientology at it’s worst is… Tom Cruise.
– The Muslim faith at it’s worst is ongoing bombings, shootings, death en-masse…

Can we make a list of religion based world issues and the severity of the threat from each faith group? All I ask is that we be accurate in the recount. No over-generalizations. Be specific where possible. :)