I can expect to dream about whatever game I'm into at the moment. I sort of look forward to it, because a usually dream a game better than I can play it. By that, I mean that the dream is better and more involving than the game, and that I am better at it.
While I cannot say I never day dream, I found the account of not being able to apply ones thought to anything else as unfamiliar. Is it just me? Games have never hijacked my thought when doing other things.
"Sometimes a sledgehammer is just a sledgehammer." That will be tickling me for at least the rest of the day! A persistent song or good line is one thing that can hijack my mind, and this may have done that.