Anecdotal lack of evidence

About two hours ago I got a really bad headache - one of those that makes your eye sockets burn and makes you want to run and throw up as soon as the room stops spinning. Even half an hour after taking painkillers it hadn't let up. Now, thankfully, it's gone. I'd love to know what stopped it so I can try the same thing again next time but I don't know whether it was:

• Having a glass of water
• Lying down for 15 mins
• My flatmate coming home and distracting me for a while
• Having my tea cooked for me
• Drinking a glass of fizzy sugary stuff
• My flatmate leaving again and no longer distracting me
• Looking at cake porn for a bit, deciding what to bake for a picnic tomorrow
• Baking the usual basic chocolate fairy cakes
• Listening to the White Album*
• The painkillers finally kicking in
• The temperature dropping slightly
• Someone in the vicinity doing a bit of yogic flying
• None, all, or several of the above

There's absolutely no way to say for sure, and no way to even come close to an educated guess. That's why next time any of my friends has a headache I won't be advising them to drink water lying down in a cool room for fifteen minutes, as someone bakes cakes for them while singing along to Everybody's Got Something to Hide Except for Me and My Monkey... not even if I thought telling them that would distract them enough to make them forget they ever had a headache. I'll fetch the water and painkillers, because at least that's worked on more than just me.

*Actually, I'm pretty sure this didn't help. The White Album is one of the worst possible things to listen to with a headache, second only to Einstürzende Neubauten.