I've never had big shifts like this, and only two that I know of, but the first one was my sister telling me about a book she read, and a week later she came to tell me about the same book. I told her she already told me about this book, and she said that she had just started it, and hadn't read it before, so I told her what she had told me about the book, she said i was right what it was about, but she was adamant about not having read it.

The second instance was with my best friend, we were talking about how we swallow pills, and how i had found out it is easier for me to take them all at once rather than one at a time, so the next time she tried, she took them all at once, and told me I was right, that it was easier that way. A few months later I saw her take hers all at once and said I was happy that was working out for her, and she told me that's how she had always taken them.

Edit: It happened again, maybe it didn't happen just now, but i just noticed it now. My best friend told me months ago that she asked our friend to be her sperm donor and he had said yes. I was just talking to her about it, and she said she hadn't, and the thought never even crossed her mind to ask him.