I was asked a question on the differences between Orthodox and Roman Catholic churches. Rather than corrupt that thread, I've tried to answer here. This is brief as I have no desire to debate theology or attack another person's faith.
Answer:
The controversy over the use of Icons was really the final straw that caused the split and while it was just one of many straws, it turned out to be a very big straw. Another issue was the "Filioque" controversy regarding the wording of the Nicene-Constantinopolitan Creed, and the matter of marriage of clergy. In fairness we should point out that there are Roman Catholic married priests in the Uniate and Oriental churches who are in communion with Rome, and the RC Church does allow Western clergy who are already married to become Roman Catholic priests (primarily Anglican and Lutheran clergy who convert).
A large difference is the issue of how the historic council of Bishops within the framework of "first among equals" over the centuries began to change as one Bishop (of Rome) began to aspire primacy over those who had been historically equals. The issue of a Universal Pope is something Orthodox reject. Orthodoxy has always rejected the infallibility of a Bishop, whether he be the Bishop of Rome or of any other individual for that matter.
The practice of indulgences is something Orthodoxy has always rejected. Other differences include after death "Toll Houses" nor the related idea of Purgatory, for example, as ideas Orthodoxy has never accepted. The Orthodox and Roman Catholic churches have different views on what happened to Mary after the ascension of Christ and differences on the communion elements and how those are viewed as the body and blood of Christ.
That is just to answer the question from the Easter thread as briefly as possible and hopefully to do so without casting doubt on those who have a different view than Orthodoxy.