The "Nirvana Fallacy", as the name suggests, can easily be used as an excuse to not improve our current performance, and/or justify said performance. For example, if you hire someone and they may do a bad job, they might justify their poor performance by saying that no one is perfect. Another title for this concept is the "Perfect Solution" fallacy, as it implies that perfection is impossible, thus we shouldn't even strive to be better.
It is beyond me why many people wonder if others may think that they are not human. Saying that "I'm only human" is no excuse for not striving to be better at whatever you're doing, when improvement is indeed possible. We should not settle for a flaw that can be reduced, and obviously, perfection is often unrealistic.
Just because perfection might not be reached at all, does not mean that our flaws cannot be worked on and be minimized in the name of better functioning. For example, we can improve our job performance by working harder and learning new skills. We can improve our grades at school by studying more and asking for help when we need it.
On the contrary, difficulty does not even imply impossibility. Just because something is difficult, does not mean we should avoid doing it, when it can benefit us in return. Using the nirvana fallacy as an excuse to avoid rewarding hardship is silly, as that would reduce the benefit we're getting in life. It would be reasonable to avoid difficulties if there were other reasons, such as not having time, energy, or having a relevant disability. However, to cancel something uncomfortable, purely because of a fantasy reality, where perfection is a dominant feature, is irrelevant to the reality we're all in.
If someone expects you to be completely perfect, AKA, lack any flaws whatsoever, then they might be suffering from a poor rationality. Whether they admit it or deny it, is a different thing. The point is that perfection, as an expectation, shouldn't even be relevant to begin with. That's especially true when the people in the conversation are rational beings.
And as a specific reader keeps reminding me somehwere, most human beings are not rational. Thus, it is reasonable to answer unreasonable answers, when rationality is uncommon. It is reasonable to not expect others to see what you see as obvious, when you are more rational than them. So when I insist that perfection is a very unlikely feature in human existence, as it is obvious to me, I am no longer surprised when it is not obvious to others.
By the way, "Nirvana" is a concept in Buddhism that is defined by the pure absence of desire and suffering. Obviously, a state of pure bliss, as desire leads to suffering according to Buddha, is a very ideal state of being. Whether possible or not among the living is another thing, as the focus in this fallacy is the assumption that a state of perfection/"nirvana" is either impossible or very, very difficult to achieve. The focus is also towards the delusional subtext, that the other people may necessarily expect us and/or our performance to be perfect.
People with a perfectionist attitude may hold themselves in accordance to this fallacy, but this isn't megalomania, where the person may they are indeed perfect. The perfectionist takes this fallacy with a great liking, especially if they are not aware of this fallacy, existing as such. Thus, they would believe that, only with perfection, they will be good in whatever they are doing. Or excellent people, in general. They may hold perfection as a basic condition, while it does not even deserve to be treated as elementary, but as extraordinary.
While it is all well and good that perfection is a rare occurrence in our world, it does not mean that we should submit to our flaws. We can become better employees, better employers, and most importantly, better people by reducing our flaws, morally or otherwise.
The same goes for rationality. It can be improved through philosophizing, or at the very least, by understanding logical fallacies properly. I try to do both, and thus, my rationality has been improving over the years. The possibility that I am, by default, an irrational being (as humans might as well be irrational) does not excuse me, nor you, from improving. I do not call for perfect rationality. I call for an improved one. As that would help us understand the truth better, which is the point of philosophy.