I heard it said that you could tell if someone had lied recently by looking at their fingernails. White spots indicated lies, with supposedly bigger spots indicating bigger lies. I've observed white spots (and damage to the nails) moves away from the lunula at a fairly steady rate... if there was any truth (sorry) to the suggestion then you could also determine approximately how long ago the lie took place based on it's distance from the lunula.
According to the straight dope the white spots (also called leukonychia) are:
The precise cause of leukonychia is a mystery. It's said to be more common in the young and in women, and often shows up when the body undergoes stress or trauma, such as a blow to the fingertips. Excessive manicuring can make things worse; so can working in a pickle factory, of all things.
The site lists many other causes of these white spots which are much more worrisome. However, getting gifts or lying is NOT amongst the causes.
If you notice white spots, also known as leukonychia, on your nails, they unlikely to have been caused by a vitamin or mineral deficiency. In a few cases, white spots on fingernails can indicate an underlying infection, but much more commonly, they are the result of injury.
The appearance of these white spots can be a result of a possible injury to the base of the nail, which is called as the matrix. Usually, these injuries would have occurred in the past, but the white spot on the fingernail takes time to appear. By the time that this white spot makes an appearance, you would have forgotten about the injury. A normal banging of the finger on the door or the countertop can result in the injury and the occurrence of white spot on the fingernail.
Again, nothing about lies or gifts. And just because we don't know exactly how something happens, is no reason to accept whatever made up outlandish tale someone comes up with....