I find it a bit amusing that for all the theorizing about why this was taken so badly, nobody seems to have mentioned the most obvious one. That is, while most people do want to know why you're breaking up with them, very few will appreciate somebody rambling on for 20 pages worth about all the things that are wrong with you. This would be true even if there had been no ev-psych content at all. ("Here are all the things about you that annoy me. First, you have small breasts. Second, you pick your nose. Third, you prefer Star Trek: Deep Space Nine above Star Trek: The Next Generation...)