Getting off on the wrong foot can doom a relationship before it begins, as we all know.

Now scientists have studied one reason why this is true. When a person makes a bad first impression, the negative feelings are harder to overcome than a betrayal that occurs after ties are established.

"First impressions matter when you want to build a lasting trust," said study researcher Robert Lount of Ohio State University's Fisher College of Business. "If you get off on the wrong foot, the relationship may never be completely right again. It's easier to rebuild trust after a breach if you already have a strong relationship."

http://www.livescience.com/culture/090108-betraying-trust.html