You are presumed to be showing us your real self when you are on deadline, have a headache, are facing a customer service meltdown, haven't had a good night's sleep, are facing an ethical dilemma, are momentarily in power, are caught doing something when you thought no one else was looking, are irritable, have the opportunity to extract revenge, are losing a competition or are truly overwhelmed.
--Seth Godin

Headaches can be divided into two major categories, known as primary and secondary headaches. Primary headaches are those that occur for no known cause, and are grouped as either migraine, tension, or cluster headaches. They are said to not be caused by an underlying medical condition, and constitute 90% of all headaches. Secondary headaches are because you have a tumor, bleed, infarction, infection, or other brain injury. Some 12% of all Americans suffer from headaches.
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