Even when there's not a joke or a hook, the first line has to be good and snapem to attention. Songs ain't novels. You don't have 30 pages to slowly wrap somebody in. They're more like short stories or poems. If the first line hasn't grabbed them, you won't get to the second line. Once you've developed an audience, you may have some luxury and trust, so you don't have to knock 'em over the head with line one.