We read in Holy Scripture: "… for this reason I have come into the world, that I should testify to the truth. Everyone who is of the truth listens to my voice," (John 18: 37). Further to the point, in our justice system, we are obligated to “to tell the truth, the whole truth, and nothing but the truth.” In all this, it is clear that telling the truth is of upmost importance and thereby forms the bedrock of good civil society. The reason that truth, and that truth being the whole truth is so important, is that each of us, through our actions and our words, day-by-day, are either part and parcel of that whole truth, and thereby are agents of honesty and integrity, or we are instead working at odds against that truth.
Intuitively we recognize that it is extremely difficult to legitimately complain or to get upset over anyone that is fully speaking the truth, even if that truth is damaging to our self, because truth, in and of itself, in all circumstances, is the highest standard that anyone can be held to; and though, we can unfairly justify our anger directed against someone that has spoken the truth in a manner in which we see that person as a "snitch" or a "rat", it is, ultimately, a futile complaint, for that which is true justifiably supersedes our own preference to be not exposed to the consequences of that truth, when such is an inconvenience for us.
The most basic reason why most everyone does not speak the truth at all times, and therefore ends up lying to others as well as to themselves, is almost always based upon protecting their own self, as well as their own reputation, and further to the point, demonstrates an unwillingness to face the consequences of that truth being told at that time. The bottom line is that people lie, tell falsehoods and stories because they do not want to be shamed or to be humiliated in front of others and especially do not want to be punished for it.
Those that tell the whole truth, even under the most extreme of conditions, and even under the knowledge that the truth told at the here and now, will subsequently have, meaningful and negative consequences for them, are absolutely courageous for doing so. On the other hand, all those that lie are basically cowards, whereas, all those that tell the truth are basically brave; for the former are often able to avoid punishment or even detection of such lies, so thereby they suffer no ill consequences for having done so; whereas the latter are those that having told the truth may suffer directly for having done so.
The more that one lies, the easier it is to continue in those lies, especially when no one else is apparently cognizant of it. So too the more that one tells the whole truth, the easier it is to continue to tell that truth, for those that are truthful, are cognizant that who and what they really are, as represented by what they say and do, is absolutely relevant and meaningful.
It would seem by the way that the world operates, that all those that selectively lie in a manner in which the perception by others is that they are truthful and honest, would seem to effectively be a successful, though somewhat compromised position to live by. What is missing from the equation, however, is that all those that have told the truth in the here and now, and perhaps have suffered from time-to-time for having done so -- clearly have paid the toll in their life by having testified to that truth; whereas all those that have taken on the guise of integrity but are not, have not yet paid their toll, and past due tolls always cost more, and sometimes they do cost a lot more.