Personally (and in reference to the original question) I found that letting go of the legalistic way of thinking that most Traditionalist Catholics seem to fall into was what did it for me. In Orthodoxy there is no Aquinas, whose theology can be seen as the point of departure from the patristic tradition in the west, so things aren't nearly as rationalized in Orthodoxy. If you really dug into Roman Catholic theology (which as a Traditionalist I'm going to assume you did) the best thing I can think of is to either A) read the Church fathers (minus Augustine) or B) go for a quick primer on Orthodox theology to get the gist so you can compare it to RC theology, the best of which I can think of is appropriately titled Orthodox Dogmatic Theology