Lying is a function of human communication. At its simplest level very many conversational exchanges are formulaic with preferred responses. In Britain the question "how are you?" has a preferred response on the lines of "fine, and you?" The function of the exchange is to establish some form of relationship between the two participants, not to convey information. If you feel terrible and answer truthfully "terrible" you have breached the intention of the exchange. If you are speaking to someone you know well you can do it, but otherwise it is a dis-preferred resonse, and often perceived as rude. When someone asks you "how are you?" they don't necessarily want to know the answer!
Someone who doesn't lie according to the linguistic and cultural conventions of society comes across as rude, aggressive, intimidating, arrogant. Lying is a necessary function of communication, and is the proper thing to do in those situations when the hearer can decode the exchange. If you tell me you are "fine" I know that this may or may not be true. Lying becomes a problem in situations when the hearer cannot decode the message.
If a guy on this board says he has a 10" cock there are two possibilities:
1) He has a 10" cock
2) He is presenting the "face" of someone who has a 10" cock because this is important to him for some reason. This is not a lie within the limited context of this board as we all know that it may or may not be true.