I'd invite you to google some of the amazing surveys/studies that have been done with abused women after a divorce/breakup. They always end up reporting something that is off with the guy within the first two or three dates. There is also vast amounts of research being done on humans instincts in being able to predict peoples overall personality from literally listening to a 1-2 second blurp of a person talking. We are highly evolved organisms which have come to dominate the planet for a reason, alot of that is because of our ability to use very little information to come to correct conclusions. Of course, there are also plenty of reasons as to why we dont listen to our instincts about people but that is best cracked open with a good therapist instead of a forum.