Nietzsche weighs in on the topic of guilt via the Nietzsche Family Circus:
IMO it comes down to our beliefs/suspicions about the nature of existence (or one's spiritual beliefs, if any).
If someone thinks the universe is entirely material and everything that happens is meaningless random chance and we're all gonna die and that's it, then the only purpose of guilt in an Evolutionary sense is to facilitate more cohesive socialization among a population since there is safety in numbers and our species only made it to the top of the food chain relatively recently.
So in this interpretation guilt has nothing to do with abstractions like "right" and "wrong." It is merely a practical necessity of our evolution into who we are.
Guilt/shame arise (in those who experience them) when our behavior strays outside of some arbitrary boundary of morals or ethics we ostensibly subscribe to or were inculcated with as children. So feeling guilt or shame is a way to reinforce social norms, which facilitates a more harmonious existence among people who care about such things (which again has nothing to do with right or wrong, and not everyone cares about such things).
So if you reject anything beyond material reality AND don't give a damn about maintaining personal/meaningful relationships with others then the rational choice is to do whatever you can get away with to maximally promote your own interests. Many do in fact choose this approach, and some make (or steal, perhaps) a shitload of money.
But if you believe or suspect that there's more to existence than meets the eye and that death may not be the end of it then how we treat others matters a whole lot and so we likewise behave accordingly.
However, promoting a spiritual there's-more-going-on-than-meets-the-eye understanding of reality while not actually believing in it allows one to do whatever one wants while denying others the right or ability to do the same (e.g., religious pyramid schemes that empower and enrich the leaders who promote religious beliefs but don't really believe them while cowing and subjugating the majority who do).
This is why I suspect that the top leaders of any given organized religion/sect are almost certainly calculating, atheistic sociopaths rather than pious believers since so many of them get busted doing stuff that sends them to their version of hell according to their own avowed beliefs, which makes no sense unless it was all just BS to manipulate the masses while they cashed in with all the money and power that cultural dominance brings. But I digress (do I ever, lol).
Anyway, if the spiritual camp is correct then being on our best behavior at all times no matter who is watching is the way to go. But if it's all just random chance and nothing ultimately matters then doing whatever it takes to maximize your own interests (up to and including harming/killing others) is the rational choice, assuming a low probability of getting caught.
It's a hell of a choice we're all being forced to make, with potentially massive implications for our material comfort while we're alive on Earth. But it's not a difficult one if we believe that other people matter. Well, not difficult to make but hard as hell to actually live with.
Psychedelics showed me (repeatedly) in no uncertain terms that there's a lot more going on than meets the eye, so as for me I try to behave and guilt never enters the picture since I don't do stuff I end up feeling guilty about. High-dose mushroom trips in particular can feel like a literal Judgment Day, after all. But if they've been lying all this time and nothing really matters and I'm just a delusional sucker who missed out on a lot of stuff I might otherwise have enjoyed because of "morals" or "ethics" then when I die I swear to god I'm gonna fuckin' kill 'em.
That said, there is also the important distinction in law of malum in se vs. malum prohibidum, which basically mean "evil in itself" vs. "evil because we say so." E.g., murder is considered malum in se while possession of a "controlled substance" is only wrong or "evil" because the law says so.
As such, there are good arguments to be made that faking a resume in a context that doesn't compromise safety (e.g., don't fake being a surgeon) might be a malum prohibidum offense in some sense but is otherwise just how the economic game we created is played so do what you gotta do.
Behind every great fortune there is a crime.
-Balzac (sort of)
As for me, I've long accepted that I'll never amass a great fortune even though I'm all about committing (some kinds of) crime. The fortune-making crimes Balzac was alluding to involve actual victims since all that money has to come from somewhere (or someone, rather).
So I would argue that it's morally and ethically consistent to be okay with (for example) selling bags of weed to make money even when it's illegal or fudging work history on a resume to get a job in most cases, but not okay with stealing someone's stuff or misrepresenting yourself in a context where doing so tangibly harms others (or risks it).
Whoa, I read your reply and began writing this one just as an edible kicked in. A good/potent one, apparently. I hope all this it makes sense; I won't be able to tell until tomorrow. 
