I firmly believe that lying is a consequence of our own nature, which is superficial and vain. For sure, as someone told above, we always have the choice, at least should, to tell the truth, however sometimes there's a situation or an atmosphere leading us to a kind of pressure that makes us unconfortable to deal with the truth. I don't think that we always are able to tell the truth, because it can hurt someone else or even not be necessary. It would be a lot better if we think truly what is more important in order to make a good thing to the ones we are dealing with, to edify them and make their joy. I'm not saying that we must lie whenever we guess in order to make someone feels okay, I'm just saying we must think seriously about the effects of some truths in our dears.
For me, that idea about telling the truth no matter what results in a huge misunderstanding of our obligations regarding to being truly people. Straightforward people don't make others feel bad, at least not desnecessarily. Those look for the benefits to these, at first.