Push-pull psychology occurs when your ex wants to be with you one minute and then tries to avoid you the next. This indicates that they are still unsure of their feelings for you and are attempting to resolve the conflict in their head. Sometimes people use push-pull as a way to keep their emotions separated from their thoughts. The reason this behavior is not acceptable is because it shows that they do not trust themselves not to take you back if you both had time to think about it. Also, they are not being honest with you - they are hiding their true feelings so they don't hurt your feelings. Finally, this type of behavior can lead to two people spending their time and energy trying to win an argument that doesn't need to be won. That's why it's important to understand that this pattern is a sign of confusion and lack of confidence, not indifference or dislike for you. If you see this kind of behavior from your ex then you should try to be patient and not press the issue. It may take them some time to work through their problems and come to a decision about their relationship with you. If after several weeks they have not changed their mind then it may be time to move on.