Headaches Make Me Slow

I get headaches. Maybe a migraine every month or two and a less horrible, headache every couple of weeks. I've gotten headaches since I was eleven or twelve, and I always took Advil for them even though Advil didn't really work. When Aleve hit the market, I tried that, and it very occasionally worked. Then I discovered Excedrin, which worked so well for me that it could even kill a migraine in less than an hour.

So I've been ill for a while (stomach issues) and I've had to give up coffee. I used to drink quite a bit of coffee, so this was a pretty major adjustment, and if I'd used Excedrin to fend off the headaches that ensued, I would never get over my addiction to caffeine. So for the first week or so sans coffee, whenever I got a headache I'd just lie down for a while and hope it wore off, and eventually it did.

Then I got a headache in Pittsburgh, and James gave me aspirin. It worked. Finally I bought some of my own. It's gotten rid of every headache I've had since then in less than half an hour.

Why did it not occur to me to try aspirin when it's one of the three ingredients in Excedrin?