Why lie? Here are some things to think about, in the realm of telling lies, or opting for the truth.
I've never quite known the answer to that. I do detest being lied to. Then again I've been in situations where it would be oh so nice to lie about something and move on. But, don't I lose...something, by doing that?
People tend to tell "little white social lies" (sounds poetic, doesn't it? Its not), in order to avoid offending or hurting others. People tell lies to avoid uncomfortable social situations, too.
Here is a way to think about getting out of these situations and what it means about you, in whether or not you do tell a lie. For myself, I never tell lies. OK, sometimes. I have been known to. However they are few and far between. Really, I greatly dislike it. In fact, I feel that if I have to tell someone a lie, typically they have governed the situation to where I've done everything I can to tell them the truth.
If someone, a "menacing person", asks me for $50, depending on that situation, but going with the understood intent harassment, theft or violence, say they mean to rob me, then they have initially broken the social contract with me of their not being menacing and not breaking the law. Once you are put in a situation like that, you are in a situation where, they are pushing you into a lie. You have no obligation to be honest with them. On the other hand....
I still find it distasteful and would avoid lying if at all possible. I see two situations, one where someone is begging you to lie to them (you may have to read between the lines on that one), and one where someone puts you in a position where you have no social or legal obligation to lie; as I just mentioned. If someone is robbing me, or assaulting me, I have no obligation to be honest with them, or to remain passive for that matter.
Once you breach the point of violence, as in protecting oneself, lies are the least of your worries. Still, I try to be as honest as the situation allows or warrants.
If they say, "You got fifty bucks?" I might answer, "That, is none of your business." Or, "How is that any of your business." You have to clarify (for them, for you).
You have to push them into either being more or less menacing. This prancing around with someone is just stupid, I won't even go to the point of saying its cowardly. They more "cowardly" you actually are, the move you should push the envelop back at them. In the end, they are either going to attack you, or not. If not, we're done, bring it to a close. If so, be on guard, let's dance, bring it on. Either way, these situations should be accelerated to a close. You're only going to humiliate yourself in prolonging it by trying to avoid a pummeling. In my experience, humor works well, honesty also very well.
Do I tell them what it is that I don't really want to tell them? No, of course not. But that doesn't mean I have to lie to them, either. I believe that telling a lie is a very immediate way to "dumb yourself down". In order to always tell the truth and not be brutal about it, one has to be somewhat intelligent. You have to "Think" your way around situations.
You might ask, what about "sins of omission"? Isn't leaving something out, lying? To that I would argue a resounding, No! If you don't want to tell someone something, avoid directly dealing with it. This changes of course, the closer the the relationship is to you, so "sins of omission" with a spouse, is far closer to a lie, than to a stranger, coworker, or anyone else outside of your family.
The second stage is to talk around it and the third stage obviously is to lie. But if you handle it correctly, if you do lie, it will be only because someone wants to be lied to. That's how it should be. Its their choice, not yours. And that's what lets you off easy!
When I have a situation where I want to avoid something, I talk around it. If someone is smart enough, they will see this; then I have to shift into saying exactly what I want to say, without saying it. This typically leaves people in a position to think the best and you are off the hook. But, if they are intelligent enough that they see the options and possibilities you are leaving open, and typically these types are a little paranoid if they push things this far, then you simply have to lie. Or simply tell the Truth.
For myself, I always opt for telling the Truth; if possible and with few exceptions. If someone is pushing you, its obvious they DO NOT WANT THE TRUTH. That means they actually know the Truth but do not want to be confronted with it. As an ethical person, you need to make a decision as to what is best for them (and at that point, not you), because honestly, they just put that ball in your court, gave you control and are asking in their own way, for you not to confront them with reality. Its weak victimology, but there it is.
In the end, be intelligent. Always try hard to tell the truth.