Leaving the Protestant church (actually, Christianity pretty much entirely) and deciding to become Catholic were separate incidents
many years apart, in my case.
The sort of ‘final straw’ that made me leave my Pentecostal church was a silly one. I was only 11 years old, and it had always been left up to me to decide if I wanted to have anything to do with church or not - and I DID, badly. I was oblivious to there being different denominations - there was just Christianity, as far as I was concerned, and I went to the church closest to my home. But I’d been increasingly unhappy with attending Sunday School - actual
church services were meant for families or adults, not kids going alone - and felt that I wasn’t accomplishing anything… I wasn’t being taught anything, just memorizing Bible verses without comprehension (or explanation!) in exchange for McDonald’s gift certificates. I kid you not.
So I decided the problem must be with
me, and I was probably too old for Sunday school and should be going to church. I think I did that 4 or 5 times, and it was horrible … just try finding a place to SIT, if you’re a kid alone.
“Excuse me, may I sit here?”
“NO!”
So I’d sit in the front pew - which was always vacant, for some reason (are they reserved or something???) - and be glowered at by the minister during the entire service.

He’d bypass me entirely for Communion (or
whatever it’s called in the Pentecostal church … no one ever explained
that either

)
So there I’d sit, feeling rather depressed, not particularly feeling like I was offering God much of anything by being there, and thinking that the other congregationalists’ attitude certainly didn’t seem very Christian. (judgmental of me, I know - but hey, I was 11. And it’s
embarrassing being stared at as you sit up front alone!)
The final straw was all these surly, unfriendly ‘Christians’ were suddenly flailing about on the floor and speaking in tongues. I was willing to believe that maybe SOME of them were genuinely having some kind of religious experience, but to me, it just seemed to be one mass ‘me too! Hey, watch me - I can do that!’
I stomped out of there thinking that God was still good, but Christianity - or people that called themselves ‘Christians’ - was for the birds. (well, the actual words I used at the time were rather nastier

)
I managed to hold onto that belief - making exceptions for some people, mind you - for about 25 years, while I searched for spiritual meaning in other religions, without luck.
I kind of stumbled across Catholicism … I’d made the decision to put some serious
study into Christianity in general, and thought that since the Catholic church was THE original Church, rather than a church that only incorporated selected bits of the original whole, it’d be a good idea to find a Catholic study bible and go from there - not really intending to ‘convert’ to
anything.
And so I started reading.
And reading.
And burying myself in the Catechism and anything else Catholic-related I could find. And finding that, somehow, anything or anyone I thought was special had
some sort of Catholic connection.
And realizing that HERE was what I’d originally thought Christianity and God were all about. Catholicism embodied the spirit that I was chasing after all those years earlier, and was so furious to discover didn’t exist within my own church at the time.
That’s the condensed version, anyway.
