Homosexuality. I “knew” that the Bible said it was wrong (fewer times than it said divorce was wrong). In college I actually met a lesbian for the first time. I had known them for months before I found it out though, so my brain was confused.
“But they’re normal! But they’re gay! So does that change anything? How does that affect me? Wait . . . That doesn’t affect me? So then what is the issue?”
I’ve never gone back to that stance.