Plot versus my inner monologue

Sometimes when I read I have these intense internal debates. Right now I am reading The Psychology of Love (a book of research articles on love and theories of love) and I find myself having strong reactions. I'll pull out a pen and write questions in the margins of the book, or underline statements ferociously while muttering to myself. Sometimes I find myself disagreeing with myself about what I disagree with. Does anyone else do that? What types of books make you react that way? It's usually non fiction for me.

If I find myself disagreeing with a book too often I'll stop reading it - doesn't happen that often though, most authors manage to at least keep some form of coherance in their arguments. I can cope with a an argument that is soundly reasoned even if I don't agree with it, but poor arguments that are full of holes I'll abandon. I don't read a lot of non-fiction though.

Similarly with fiction if the characters act belivably for their setting I'm fine, but unexplained deviations from normal behavior annoy me.

I'll never write in the book though.

I find myself debating with myself over the most random things that I read. Some phrase will just stick in my head and I won't be able to continue reading until my thoughts have played themselves through.

I read mostly fiction too, so it might even be a joke or image conjured up that will set my mind going.