Lie and Man Deciphers Truth

As a society, we have become so accustomed to metaphors and empty truths that we absent-mindedly accept them. But if society is told a lie and believes it, does that turn the lie into the truth? For example, in the beginning of the human's reign on this planet, humans thought the earth was flat only to be proven that the earth was in fact round. But if ordinary humans were told that the earth is flat and they accept that as the truth, live their life as though it is true, then what makes it untrue? Someone must come along to convince the population that their truth, the earth is round, a valid and have it be accepted. Nietzsche mostly talks about how man deciphers truth in his essay; however Nietzsche cannot avoid mentioning lying because in reality, lies and truth are very intertwined with each other. In fact, there are times when the truth and lies are so entangled that there are indecipherable from one another. If there is such a thin line between lies and truth, why do we lie rather than tell the truth? What exactly is the difference between someone who knows they are lying and someone who lies unknowingly? What is the difference between a different perception and a lie?
In Friedrich Nietzsche's essay, "On Truth and Lies in a Nonmoral Sense," he determines that language, and therefore human knowledge, is a construction of metaphors and concepts. Language is designed in order to allow individuals to understand their world and come up with what they believe to be "truth" when in all actuality; truth cannot be defined because it is based on ones personal knowledge of the world. Nietzsche says, "[the truth] in short, [is] a sum of human relations which have been poetically and rhetorically intensified, transferred, and embellished, and which, after long usage, seem to a people to be fixed, canonical, and binding." (Nietzsche, 455) To me, truth reminds me a stories that have been passed done throughout generations but as they get passed down, the story changes