The Talmud says we see things as we are not as they are.  I can only guess the number of times I assumed that something was true about someone only to find out I was wrong.  Thank goodness I didn't always act on my assumptions.  I regret the few times I did.   I've discovered that when I've taken the time to ask questions, that time was not wasted.  And of all the questions that come to mind, the question "why?" is without doubt the most important.