I didn't know just how much faulty logic I used in talks at the Kingdom Hall until I properly freed my mind. And even where I disagree with people on things now, I try to understand why they think the way they do.
One huge thing I have gained is learning what anecdotes are. Another is to have a healthy dose of scepticism.
But I don't reject things automatically just because they are difficult for my imagination - a multiverse or the big bang. Heck, even though I am atheist, I am willing to see actual non-anecdotes in the form of evidence of a creator. Until it presents, I am just not willing to embrace the gods of men.
Conspiracy theories are tough, though. Some seem to make sense, but evidence is typically just anecdotes. I mean, most religious beliefs seem born from conspiracy but evidence is hard to come by.