This is not how discussions work. A: I think X. B: Interesting, why do you think that? A: I have 10 years of thinking about it. B: I have 10 years of thinking

This is not how discussions work. A: I think X. B: Interesting, why do you think that? A: I have 10 years of thinking about it. B: I have 10 years of thinking about it and have the opposite opinion. A: If you're suggesting I'm not telling the truth then it's not possible for us to have a good faith discussion on this topic. I might've made a fallacy, but this is what popped to mind when I read this comment.