She turned you into a newt?
At least, that's what the villager in Monty Python claimed. But unlike most people who recover from some condition, the villager continued to obsess over it, telling the local lord, "She turned me into newt!" In some ways, this villager is much like the average apostate Catholic.
Consider those people you know who are converts to Catholicism. Think of how they self-identify when describing their religious beliefs and what their attitudes towards such identity are in general. Now, mentally compare these same attitudes and identities with those of people you know who have left the Catholic faith. If my experience and that of people I know are indicative, these two groups of people are vastly different. Catholic converts tend to identify themselves just as "Catholic," and offer details about their former beliefs only when asked/when relevant or perhaps as a symptom of giving too much information in general. Catholic apostates, on the other hand, have to let you know that they've left the Church. They obsess over and revel in being "ex-" or "recovering" Catholics. Almost invariably they combine such self-identification with almost uncontrollably vitriolic detestation of the faith.
I find this phenomenon truly fascinating, and indicative of the truth of Catholicism. The glue that holds the Church together is, as Christ foretold, indissoluble. It can be corrupted, however, torn from its original use -- the apostate attempts to sink the bark of Peter by pulling the caulk from between the timbers, yet only mires himself. Apostasy is like a tar baby, in which the individual traps himself in the goo of an otherwise efficacious sealant. The apostate cannot rub out the marks that have been seared into his soul, and he cannot sever the bonds that tie him to the Church -- all he can do is chafe and vent.
As I believe Chesterton said somewhere, men are never ambivalent about the truth. One loves the truth, or one can hate the truth, but one never simply abandons it and walks away blithely.