Argyria is a condition caused by improper exposure to chemical forms of the element silver. The most dynamic and unusual symptom of argyria is that it gives you the physical appearance of an unhealthy Smurf; your skin usually turns a blue-grey color.
This is because in humans and animals, silver actually accumulates in the body (it does not get broken down or converted), and thus can result in an excess of silver particles in the skin. These particles darken with exposure to sunlight, resulting in the blue or grey discoloration of the skin.
Argyria is believed to be irreversible, and the only practical way to prevent the cosmetic disfigurement that it brings is to avoid the sunlight. So what would you choose; no sunlight, or forever looking like a really sad Avatar?