I believe false doctrines happen,because someone has a belief that is not part of the Bible,and they drag it in to the Bible,and it becomes their foundation for interpretating scripture.
Everyone does not see the same thing in the Bible unless they take the Bible for what it is,and do not drag anything in to it,and you cannot fully understand the Bible unless you are led of the Spirit,which not everybody that claims Christ is led of the Spirit,which God said they have a form of godliness,but they deny the power thereof,ever learning but never able to come to the truth.
Everyone has a belief about reality,and what they consider to be the truth,but not everybody when they accept the Bible take the Bible for what it is,but might hold unto a belief that is not part of the Bible,and interpret scripture according to that belief.
It is like Joseph Smith,who had a belief that was not part of the Bible,and dragged it in to the Bible,and it became his foundation for interpretating scripture,and many others like him.
That is obviously what happened with the Roman Catholic Church,that instead of abandoning their pagan ways,they held unto them,and it became their foundation for interpretating scripture,which they are interpretating according to the flesh,which I know Catholics love God,but the Vatican and the Pope should know better.
And that's the thing,a lot of people are interpretating the Bible according to the flesh,because they have a belief that is according to the flesh,and since so many people have varying opinions concerning things,there will be a lot of different interpretations,but not so much as now with the new age movement,and their interpretation of the Bible.
The theory of evolution has created quite a stir,that the new age movement has an interpretation that believes in evolution,and exalts people,and diminishes God,based on the occult,and witchcraft.They interpret the scriptures according to witchcraft beliefs.
That is what they belief according to the flesh,so they interpret the scriptures according to that belief,and the people in the occult are far more arrogant,and self exalting,than ever before,why,because of evolution,which took God out of the picture,so there is no God to fear,and no God to offend,for their highly arrogant,and self exalting ways.
We live in a world of so many varying beliefs concerning reality,and how people want to hear things,so there will be varying interpretations of the Bible,because many that believe will not want to hear it according to the truth,which the biggest area they lack is they want the flesh to have some control in their life,and to exalt themself.