I'm continually surprised how difficult it is for people to understand the nature of ego drives (instincts) in Freud. I understand the confusion between the ego drives and ego ideals within Freud's writings but whatever you want to call them they remain the most important part in Freud's Copernican revolution of showing how the ego isn't master in its own house.
This revolution is in opposition to the simple Cartesian view of a person being a rational chooser who decides what he or she wants to do with his life and who must satisfy the bodily needs of hunger and sex and deal with the passions that interfere with his rational thought. People might add a little to this and talk about 'habit' (existentialism) or amplify hunger and sex and add desires that are informed by discourse or repetitions of childhood relationships, however this dualism basically holds.
What Freud does with the drive/ego ideal is point out that one is forced (driven!) to go after success, love, being loved, being the smartest, etc. and desires are part of our character and not things an adult chooses because he has decided that being regarded as a good athlete is a better way to live than to help the disadvantaged. Moreover, he points to their negative quality or 'Faustian restlessness' in that once one finds success, say for example, a person finishes highschool near the top of his class, there will be a feeling of triumph as ego (self) coincides with ego ideal, but that this feeling will wear off and a new object will be found for the ideal. Now the person must be top of the class in college or be regarded as smart in a profession.
To not go after the ideal or feel like one wont' live up to it is dynamically related to feelings of shame, inferiority, guilt, self-pity, (etc.)- all of which is common language and any person who is wise can see in others.
To be found in Freud's writing is the additional claim that if one tries get rid of these feelings that follow from the non-fulfillment of the ego ideal one must repress it, which will involve a return of the repressed and a compensatory neurotic trait. Additionally, in his idea of defusion of eros, that covers both egoistic and competitive drives and altruistic drives of finding harmony with others, is the idea that to attack the object representation or imago of the parent upon which the ego ideal was formed will lead to the death drive emerging. In 'On Narcissism' Freud shows how that this will lead to the regression from looking for success and love to hypochondria or some other lower functioning (i.e. phallic to anal) that isolates one from competition or love with others. It could also lead to the furthest regression of catatonic schizophrenia in which one has next to no contact with others.
Thus the rational chooser and the 'reasons' why he chooses to work hard and find success are rationalizations for Freud. This person is not free to choose. He has ideals and to not fulfill them causes him to feel shame or inferiority before people and if he suppresses the ideals he will suffer neurotically for it.
The drive/ego ideal is Freud saying we are primarily social beings first and our drives and ideals show this need for recognition and love from others. Reason is applied to realizing these desires but it is secondary or practical.