A week ago, I had my first migraine headache (or at least, the first time I identified it as such). It started out with an aura, or visual disturbance. It's very hard to describe this visual disturbance, but it was like my vision was fractured, smeared, and/or occluded in certain parts of my visual field, particularly in my left eye. I was still able to read, but had to move point my eyes in different directions to find places that were still functioning, much like one might do after staring at a bright light. This was actually the most unpleasant part of the experience by far, since at the time I wasn't sure what was going on and something like a stroke seemed a real possibility.
I started reading Wikipedia, and one of the things they said was that auras generally last less than 60 minutes. Sure enough, in a bit under an hour my vision returned to normal, and around the same time I started to get some pain which was completely localized to the right side of my head. It really wasn't that bad, particularly after I took some Excedrin, but as I was also nauseated and I wasn't quite sure what course the thing would take (i.e. whether it would get worse) I decided to go home from work. As it turned out, after a nap of a couple of hours I was basically fine.
One could say that this ought to disturb me, and if it starts to become a regular occurrence it probably will. But my reaction this time was “hey, that's kind of neat”, as I managed to identify it (echoing my self-diagnosis of diabetes many years ago), it followed the pattern to a tee, and it really wasn't that bad anyway.