In Psychoanalysis, according to Sigmund Freud, this is the component that is developed because of the Id. It is the formation of internal standards (most importantly included are morals). The superego strives for perfection. This component is initiated by the pressures of parents, peers, and society.
I only got an A- on my math test. I am not going to get into Harvard. My lack of college education will mean I will have to work as "cockroach" patrol at the local grease spoon. I won't be able to make ends meet SO I WILL HAVE TO ROB A BANK! I'LL GET CAUGHT AND GO TO JAIL! MY CHILDREN WILL STARVE TO DEATH BECAUSE I CAN"T FEED THEM. STOOOOPID MATH TEST! You ruined my life! <sob, sob, uncontrollable crying> The cause of the anxiety is the superego hunting for perfection.