My theory, disputed by many doctors, is that the human brain has tiny fishing hooks inside it. Not a lot of them, maybe half a dozen. They just kind of sit there hanging out into the open thoroughfares that our thoughts pass through. Most thoughts, especially the important ones (“hey, remember to pay your credit card bill”; “this person looks like a Mike but his name is actually Greg and he will get mad if you screw it up”), zip right on by undisturbed, sometimes gathering the escape velocity to shoot straight out of your head completely. Sometimes, though, a thought gets stuck on one of those hooks, and then it just stays there, wriggling around, refusing to leave no matter how hard you shake and jostle it. They’re usually useless ones, too, like facts you have no need to remember (“Liam Gallagher owns over 2000 tambourines”) or song lyrics that haunt you for decades (“Man, it’s a hot one…”). Every now and then, though, an idea will get snagged. A really good one. One that someone else might have tossed out as a joke and forgotten about but stays on the hook in your brain for weeks, shouting at the other thoughts passing through, altering each of them, and consuming you completely.