God's Holy Spirit tells me I am right.
Once upon a time, I found myself on the same message forum as an individual who had this same attitude.
By his own admission, he'd only been a member of his current denomination for about six months, hadn't read the Bible cover-to-cover, and in fact didn't think anyone even
needed to read the Bible all the way.
Rather, the way he saw it, he was a member of the "right" form of Christianity and so he was "right" by default.
Problem was, whenever he tried to challenge me, he'd do so with canned arguments he got from somewhere else. It didn't take me too long to knock those down, often because those arguments had been around so long someone else had already dispensed with them some time ago.
He couldn't square this with his presumption that he was "right" by default.
Before too long he was literally just copying and pasting entire pages of anti-Mormon material and going on long-winded rants whenever I'd knock his material down again.
Eventually, the guy had a full psychotic break that led to his going on massive rants and generally becoming verbally abusive towards everyone. In short, if we didn't drop everything and believe as he did then we were all damned, regardless of whether or not he could back himself up. He was banned from the forums soon after, and there's reason to suspect that he was the one behind at least one of the denial-of-service attacks the site suffered in the wake of his banning.
He may have been a particularly dramatic example, but... talk to any one of us who's been doing apologetics work for long enough and they'll have at least one story about someone who deteriorated just like this: they were convinced that they were "right" by virtue of their religious affiliation alone, hadn't bothered to actually study the matters at hand, relied heavily on the work of other people without actually fact-checking it, experienced cognitive dissonance upon discovering that what they were told wasn't correct, and suffered varying forms of mental trauma because of it.
Once upon a time the term "My pastor knows better!" actually became something of a punchline, as whenever confronted by the realization that whatever their minister told them might be incorrect people would rush to defend their minister rather than stop to assess what they'd been given.
So an attitude of "God's on my side no matter what I do" isn't exactly going to guarantee one anything beyond heartbreak.