If I think something is wrong, my first reaction is one of actually feeling that something is wrong. Whatever it is offends my nature. It might be something where I simply feel disapproval, but, depending on what that'something' is, I might feel disgust, revulsion, sometimes even tainted with fear. I then try to consider the situation and assess it according to my values in as rational way as possible. This may well mean that I have to consider other people's points of view. The end result is something which I would call my moral opinion, however imperfect it might be.