I think that, in the interest of being a good human being, you should strive to be truthful. That said, in this world, lies are necessary. Modern life could not be sustained without lies. Let's be realistic here, we as humans cannot handle 100% of the truth, 100% of the time. This is why, in my opinion, omission is a beautiful thing. It's not the whole truth, but it is not quite a lie either. If I answer a question using only the info that I thought was necessary to answer that question, that should be fine. If it is later known that I had more information than I disclosed, I can always say that you did not ask me about that. I gave you only the information that you requested of me. Lies also help avoid small and unnecessary problems in life. If it is a trivial thing that will have no significant negative impact, then I don't think that lying about it is such a big deal in the grand scheme of things.