In the introduction to his book The Possibility of Practical Reason, Velleman suggests that "reasons for acting are the elements of a possible storyline along which to make up what we are going to do." (p.28) We are driven by a need to understand ourselves, to live out a coherent and comprehensible story. Subconscious desires may cause us to behave in certain ways, but this is "mere activity" in contrast to full-blown intentional action. The former still originates within ourselves, from our beliefs and desires. The difference in case of mere activity is that we do not (concurrently) understand our behaviour. We may work it out in retrospect, but then we have discovered something about our life story, rather than creating it ourselves.
Intentional action results from a prior judgment that the action in question makes sense to us, that it would fit our story well. We decide what comes next in the story, and thereupon act to bring our actual life into line with the narrative. (See Velleman's 'The Self as Narrator'.) Other times our behaviour is less transparent to us. We must reconstruct a plausible story which might explain the behaviour. Even if we eventually come to understand our past activity, the fact remains that we were not acting upon our self-understanding. Our narrative faculty merely responded to the action, rather than causing it. Such failures of authorship are at once failures of agency.
Agency is authorship. That's one kind of story. Another concerns our nature as social agents. Humans are self-presenters. We spin a story, a public 'persona', to present to the world. As Velleman writes in 'The Genesis of Shame' [PDF] (p.36):
[O]thers cannot engage you in social interaction unless they find your behavior predictable and intelligible. Insofar as you want to be eligible for social intercourse, you must present a coherent public image.
He goes on to extend the Gricean analysis of intentional communication to other modes of social interaction (pp.36-37):
[O]nly when your movements are recognized as aiming to be recognized as helpful do they count as fully successful contributions to cooperation... Full-blown social intercourse thus requires each party to compose an overt persona for the purpose, not just of being interpretable, but of being interpretable as having been composed partly for that purpose.
Note, then, that self-presentation is not a dishonest activity, since your public image purports to be exactly what it is: the socially visible face of a being who is presenting it as a target for social interaction... you aren't pretending, in other words, that the itches you scratch are the only ones you have.
There are limits to how much we wish to include in our public stories, as Nagel notes in 'Concealment and Exposure':
We don't want to expose ourselves completely to strangers even if we don't fear their disapproval, hostility, or disgust. Naked exposure itself, whether or not it arouses disapproval, is disqualifying. The boundary between what we reveal and what we do not, and some control over that boundary, are among the most important attributes of our humanity.
Velleman argues that it's the loss of control over this boundary which elicits the emotion of shame. An unzipped fly undermines your status as a self-presenter, which gives rise to shame because we are naturally anxious about potential 'disqualification' from the social sphere. Note that this account explains why we can feel shame even when there's nothing we're ashamed of -- "we needn't feel denigrated in order to feel undermined in our self-presentation." (p.43) Velleman further notes that deliberate self-exposure has no such effect (p.38, e.g. Playboy models), unless it also leads to some unintended self-exposure. He also observes that humility pre-empts shame, "by deflating our pretensions and thereby rendering our self-presentation consistent with the criticism that we face." (pp.42-43)
There are interesting questions to be raised about the relation between the two kinds of 'stories' discussed above. Though our public persona only tells part of the full story, I think it still needs to be accurate in what it does present. Otherwise you get people who seem "inauthentic". The story they tell is not really their own. But it is important that we're not always forced to tell the whole story, as Nagel notes:
[A] culture of selective reticence... permits the individual to acknowledge to himself a great deal that is not publicly acceptable, and to know that others have similar skeletons in their mental closets. Without reticence, repression -- concealment even from the self -- is more needed as an element in the civilizing process. If everything has to be avowed, what does not fit the acceptable public persona will tend to be internally denied...
The public gaze is inhibiting because, except for infants and psychopaths, it brings into effect expressive constraints and requirements of self-presentation that are strongly incompatible with the natural expression of strong or intimate feeling. And it presents us with a demand to justify ourselves before others that we cannot meet for those things that we cannot put a good face on. The management of one's inner life and one's private demons is a personal task and should not be made to answer to standards broader than necessary.