When my faith is at all shaken, disputes among believers probably shakes it more than anything. We are all supposed to belong to Jesus and have the spirit dwelling within us, but it is amazing the differing interpretations of scripture there are.
My personal opinion is that many of those who are adamant about certain doctrines, spend too much time listening or reading only one or two theologists. We must remember they are human only, and the bible should always be our final Word. I almost fell into this trap myself.
So many times I have heard people say things like :So and so ( insert theologian )says this" and "So and so says that". I have actually asked them, "What does God say"? Sadly, many times they can't answer my question as the doctrine of man is the only thing they remember or their answers relating to scriptures are those which take a verse or two out of context and twist it so that it isn't even recognizable as the word of the Lord.