Without understanding Human psychology, peaple r dealing/treating human beings. what is your openion?

obsolutely right. By learning the most advanced new psychology like Transactional Analysis & Neuro Linguistic Programming we can understand how the human being are structered and easy communication. 

Maybe you right? Human life quality depends on our quality of communication with who? with our self and with other. So to del better with others you need to communicate better, and to communicate better you have to know their psycology better. and to know their psycology you have to communicate to them :-). You like my answer righ?