Theists (especially Christians), has this happened to you?
Whenever I have a conversation with a person and as we're talking the person says "Well, the Bible says..." or "Jesus said..." my brain automatically shuts down and I don't hear anything else said. Not to be rude, of course, I just cannot force myself to take anything a person says seriously after that.
Have you ever had a conversation with someone and that person's eyes just glazed over and you don't know why?
You apparently have missed the point. I have intelligent conversations with intelligent Christians on a regular basis (my boss is a very devout Baptist), but whenever a person isn't able to form a personal opinion or come to a conclusion without the help of a Bible verse, it doesn't show much intelligence.