"Good" student and "Good" teacher

I often think of the society's view on who we consider a "good student". One, who sits straight, follows instructions, obeys the rules, raises hand to talk, does the homework, etc. Right? And then who is a "good teacher"? One, who makes the instructions, can enforce the rules, will assign the homework, and knows all the answers ahead. Pretty accurate description of the society's view on school and how it should be. This view on school and schooling stayed unchanged for over 2000 years and everybody was happy. So, why is that today neither students nor teachers feel happy about that ideal picture? Maybe because we don't want to live in an ideal picture; we want to live our real life. Reality is not perfect, it's not clean or quiet. Reality is messy and complicated. In reality nobody knows the right answers and very often what you thik is right for you turns out to be very bad for someone else. How can we teach that?