In their heads

 I would love to get into somebody's head to understand how they think, what goes in their minds as they hear something or their thought process as they make a decision. 

If I get into their head as myself I wont get a 100% understanding of what its like to be them. If I somehow manage to become them 100%, I wont get an understanding, because I have become them. 

So we are doomed to live with incomplete understanding and the consequent befuddlement as others choose something that makes zero sense to us. So our inability to understand someone is usually not a lack of  communication or misunderstanding. A close analogy I can think of is lets say you are describing furniture in a house- however accurately you describe the furniture, if you and I are imagining different empty houses to put them in, our end results will be that different.

So we should cut ourselves some slack for the inevitable miscommunication that happens.