All hits somehow tap into the zeitgeist of the moment – whatever people are thinking about in the world, in popular culture, they somehow snag a portion of that and represent it musically. I know that sounds esoteric but that’s what it is.

Part of it is having a great hook, some kind of memorable refrain or musical moment that people can’t get out of their head – like an infectious worm in your brain. That’s part of the craft ...