Behavioural change is needed because we're creatures of habit, and we seek the most expedient way to get what we want. This goal-seeking builds patterns or habits that make things happen for us. 

For the most part, we work on automatic pilot.  Who hasn't driven a car home and not remember driving?  

We do the same thing with talking to people and communicating. 

This auto-pilot mode is called automaticity, useful in many situations but essential to step out of when you are engaged in important conversations.