In my opinion, Catholicism (for all it's good qualities) is too theoretical and abstract. It's easy to walk out of church without any real takaways that you might apply to your ordinary life.
It hit home as a teenager during Easter Sunday mass. A priest enters the church, wearing his extra religious garb, a crucifix is carried behind him. The procession take several steps, the worshippers then kneel down and immediately stand back up. Several more steps, then kneeling and standing. Then several more steps, then kneeling and standing.
The third time I stood up I felt like it was outside my body looking at myself. Following the crowd with absolutely no idea why or the meaning behind it. To me, I looked like an idiot. My father was religious his entire life, so afterwards I asked him what the ceremony represented, he had no idea. I went to church less and less after that.
Earlier this year I attended a 90 minute "walkthrough" of the mass where my priest explained the structure and meaning of a normal everyday mass. At the end of it he had still only scratched the surface, but it was probably more explanation than most (ex-)Catholics ever receive on the topic.