Nostalgia

It is an illusion that youth is happy, an illusion of those who have lost it; but the young know they are wretched for they are full of the truthless ideals which have been instilled into them, and each time they come in contact with the real, they are bruised and wounded. It looks as if they were victims of a conspiracy; for the books they read, ideal by the necessity of selection, and the conversation of their elders, who look back upon the past through a rosy haze of forgetfulness, prepare them for an unreal life. They must discover for themselves that all they have read and all they have been told are lies, lies, lies; and each discovery is another nail driven into the body on the cross of life. 

 ― W. Somerset Maugham, Of Human Bondage