These days, you often hear that line in the press and in the title of a book by a rather pompous two-bit academic, who WILLS remain nameless. In those cases, it's usually a preface for a rant on why the Church needs to stop being stubborn and bow down to the superior wisdom of whoever is doing the ranting. Praise God, there's a new trend. Every day, I find more people who use that line as a preface to a serious discussion of what's good about the Church.
As for me? Well, I can be a bit of a pompous windbag at times, but, on this subject, I'm completely in earnest. Why am I a Catholic? Well, I could give you a thousand reasons and keep us both up all night, but they would all be incidental. They'd all be secondary. They'd all pale in comparison to the one most important reason why I'm Catholic.
I am a Catholic because I'm absolutely convinced it's true. That's it.