I grew up majorly Catholic, went to a private Catholic school for most of my formative years, with the school uniform with the crest, sang in the choir, had mass five times a day at school and then again at church on Sunday. As I went through confirmation, I began to have serious doubts about the church, then they dragged us into the church basement less than a week before confirming us and made us watch a bunch of films that laided down the pro-life thing, the anti-masterbation thing, the anti-contraception thing, the anit-sex-before-marriage-thing, the everyone-else-is-going-to-burn-in-hell thing, etc. I felt really betrayed since none of said topics were ever addressed in the seveal months of study before hand, and when the films were shown, there was no discussion allowed afterward. It totally turned me against the church.
The next week I actually cheated on my confirmation exams - instead of memorizing my prayers I wrote them on my thighs and wore shorts that concealed them but could be pulled up so only I could look down into my lap and know what I was doing. I don't think I could have done anything more counter to the religious training I was supposed to have recieved. It's kind of funny and kind of sad.
I went through the whole thing for my parent's sake, my heart was totally not into it. I had a lot of questions that no one was really willing to talk about. I ended up in a public school that year, changing in the middle of the school term due to some fairly extreme bullying. I know almost everything you'd want to know about Catholicism, but I'm definitly not a Catholic.