This is just my own knowledge and my own experiences, so please, if I’m incorrect, please feel free to correct me.
In general, the Orthodox and Catholic Churches are very similar, with few differences, relatively speaking. The Orthodox Church views the Catholic Church’s Sacraments as valid, so there isn’t a huge issue there. The main difference between the two is the fact that the Catholic Church has a Pope, and the Orthodox do not believe, nor do they agree with the fact that a man stands in the way of God. Not my words, but the words of a fellow Orthodox acquaintance.
From most of the Orthodox I have met and know, they have a strong dislike for the Catholic Church, and it really confuses me. And when I say strong dislike, I mean they cannot stand it. Now this is most certainly not the case with all Orthodox. I know of one person who absolutely loves the Catholic Church, who has absolutely no dislike for it, but doesn’t really want to be a part of the Church. So, for those who have run into the problem of the Orthodox hating Catholics, it’s not everywhere in every Church, but it is quite common, especially among the Greeks. But, there again, it’s just from my experiences.