It's good to get to the bottom of a thing. To know the issue inside, out. The best way to do it is simply ask - simply ask why ? When you ask why, you admit your ignorance. You also make it incumbent on the other person to give an answer. The answer throws light on the mystery, on the darkness. It's good to be inquisitiveness, it's good to be a learner, it's good to question, question by asking a why.
To gain knowledge is good. We do that by investigation. By being inquisitive. But when we convert this same inquisitiveness to asking questions on human behaviour it can become irritating, demeaning, or even insulting. Ask someone why they are so aggressive, or so timid, or so gentle ? Ask them why they behave in a certain manner. When you do this you will be pricking a raw nerve in that person. You will be liable to cause hurt because the very fact you questioned is a testament to your not accepting the present state of his behaviour.
Behaviours vary. You may not understand many of them. Because each of us can't read the other person well. Some people are very poor in reading people, and some people read only some people well. Very few have the knack of reading every person well. Behaviours perplex us, confuse us. Often they disturb us, hurt us. We often try to control the other person's behaviour by asking uncomfortable questions. Control is weakness, coming out of fear. Don't control. It's better to allow each individual to freely express himself, not feel bound in his behaviour. For someone to feel free, he must have comfort in the fact that if he behaved or acted in a certain way, he will not be asked why. When you give freedom, you earn freedom for yourself. The best way to earn your freedom is when karma will reciprocate your habit - your habit says - "don't ask why".