I'm guessing you tried to receive the Eucharist.
No... It was when I joined the military. Every one had to attend church. Since I didn't know if there was an Orthodox church on the base, I attended the Catholic Church. They locked the doors and made everyone confess. I had never confessed in my life. We were escorted to a room with multiple chairs and tables where multiple priest were taking confessions with only a screen divider on the table separating the priests from the soldiers.
A gray haired, bearded priest welcomed me, and in so many words said I could start confessing. I told him that I didn't have anything to confess. He looked at me through the screen, and said, "oh yes you do"... I knew that I wasn't getting out of there until I confessed something so, I said," well I do have one thing to confess ". He smiled, put his ear back to the screen, and I said," I'm Greek Orthodox, and I don't think I'm supposed to be here ". All of a sudden, his fist slammed on the table, he jumped to his feet, and yelled..." YOU'RE WHAT!!! ". As I tried to melt into the floor, he caught himself, and in a calmer voice said in so many words, that there was an Orthodox church 10 miles away, (mind you, it was over 100 degrees Texas heat. I thanked him, and crawled out the door. I've always wondered what the other soldiers thought... What in the world kind of heinous crime I could have done... But I'll never know.
There was a time, (and its still the case), that the Eastern Orthodox Church, and the Western Catholic Church didn't, and doesn't, get along. If you want to know the history of the conflict, it will take research, of not only church history, but history books as well. Even then, as with all conflicts, I doubt the causes could ever explain the reasons for the schism.
The main reason that I've been told was the demand of the Roman Catholic Churches demand that the Orthodox East agree to the Pope's Claim of infallibility.
When the demand was vehemently denied by Constantinople... All help against the Turkish Muslim's was denied by the Pope, and Constantinople fell. Without theological competition... The Vatican Cities power went unchallenged, until Martin Luther.