Life in the society is always in a everchanging environment, just like what is taught in school, how much will the knowledge be applicable in real life. As everyday we spent on and worked in life, we learnt something new. Knowledge can be imparted but experiences can't. They have to be experienced in order to be gained and applied to life.
It's up to the individuals to perceive these thoughts and never think life's out there as good as it was in school. Think of it as the school as the womb that encompassed us for at least a period of time before we were borned into the world, once into the world, we have to learn how to breathe, eat, crawl, walk and so on. Very much like so in real life.