I think that Mark Twain had it right when he said that we are all liars. He may have said it in jest, but perhaps he was alluding to our growing use of the lie and what constitutes a lie. As Chris Rock observes, women provide the "visual lie," especially when dating. For example, women put on high heels when they aren't tall, they put on makeup to disguise how their faces really appear, and they wear the Wonder Bra to make their breasts look larger. With men, it's the "actual lie." They act differently than they really are when they are dating such as appearing to be interested in their date's hobbies when they really aren't. Then there are more profound lies such as lying to your mate about your fidelity. Which lies are "really lies," are lies wrong, and are some worse than others?
According to Charles Fried, even "[a] little lie is a little wrong but still something you must not do" (205). Immanuel Kant describes the issue as a "duty of veracity, which is quite unconditional" (198). Henry Sidgwick, however, has the view that "lies [are] sometimes justifiable under certain circumstances" (216). While Immanuel Kant and Charles Fried appealed to the deontological view that lying is wrong and regardless of the consequences one has a duty to not lie, others such as Henry Sidgwick have appealed to the utilitarian view that lying in and of itself is not inherently wrong and that a person needs to only consider what actions create the best consequences for everyone.
As rational beings and as part of the human contract of interaction, we have a duty to protect and to not impede an individual's rights and autonomy. There is an intrinsic value in a person's autonomy. A person does not have autonomy unless he or she has the psychological capability for rational decision making that is based on the truth. Any action that limits or deprives another person of their autonomy is bad and an intentional action to do this is morally wrong. Perhaps it is not a universal law that lying is wrong, but being lied to causes a person to have a view of the world that is different from reality, thus depriving them of their autonomy. Lying is also inherently exploitive and manipulative. Each person has a right to make informed decisions that affect his or her life without being manipulated by another person's lie.
It is wrong to lie most of the time, for most reasons. However, the "visual lie" as described is not necessarily a lie because the truth is obvious. Even with the best of intentions and believing the consequences of the lie will be positive, there is never a guarantee that the result will be positive, won't result in someone losing their autonomy, and won't be exploitive or manipulative. In a few situations when telling the truth would result in severe physical or emotional harm to another person or yourself, you can appeal to the utilitarian view that not lying will have far worse consequences; the lie itself is still wrong but not lying is more wrong. Truly, in those situations when the reasons for telling the truth are not clear, one must use their best judgment and take responsibility for their actions. A lie always has the potential to cause harm.