I am going to address this chiefly to the christian church (and it various offspring), but it concerns all other forms too.
My view on religious people is that they are highly gullible. They continue to believe everything the bible says as concrete fact, despite the number of times the church has been proven wrong in the past. Examples of this is the earth being a sphere and the earth going round the sun. So, continuing to believe in what priests and their ilk have to say is like hearing a thrice convicted child molester say "I promise I won't do it again" and believing them.
On the whole, I have no actual problem with religious people, but when they start interfering in other people's affairs it gets annoying. A good example of this is when a church group started protesting outside some poor soldier's funeral service because they believe that god hates the war or something equally stupid. Those silly churchies can believe what they like, but they should at least have the decency to leave people alone while they're attending a funeral.