Several years ago, a friend turned up at my house who I hadn't seen for some time. Initially pleased to see him, I got concerned when it turned out he had had a breakdown and had then found god. As in found == full blown fundamentalist, as it's written in the bible, speaking in tongues etc.
It got worse as he spent the evening telling me that, I was still a dear friend of his. However he could see demons standing behind me and it was his duty to save me.
It was a truly horrible and scary evening, having to listen to an old drinking buddy now spouting the craziest nonsense.