From Scientific American comes an article on boredom.

For most people, boredom is a passing, nearly trivial feeling that lifts as soon as your attention is required for a task or an entertainment. But easily bored people are at higher risk for depression, anxiety, drug addiction, alcoholism, eating disorders, compulsive internet surfing, hostility, anger, poor social skills, bad grades and low work performance. Probably halitosis and hangnails, too.

Men generally are more bored than women and exhibit more risk-taking behaviors, report enjoying more dangerous entertainment and are more likely to say that their environments are dull.

Causes? Perhaps a lower level of endorphins? Perhaps a lack in early education to entertain/amuse yourself? Early consistent exposure to excitement and sensory input leading to an intolerance to a perceived deficit? Boredom therefore leads to lifelong sensation-seeking behavior.

During my childhood, I had long stretches devoid of human company or external stimulation (radio, TV, etc.). I amused myself by reading, making dolls' clothes, climbing rock cliffs, swimming, collecting seashells, going for walks with my dog. I was never bored. It never occurred to me that I was in some kind of want, suffering some lack of stimulation.

As a result, I am comfortable with time alone. I am capable of intense concentration on a task, and I enjoy both solitude as well as companionship. Deprived childhood? Hah! I'm one of the lucky ones.