While I do see TKirby's point, I always felt like this song was about lust, rather than unrequired love.
He portrays himself as a guy who wants a woman badly, and it surprises him, because he's not usually that way ("I know who I am when I'm alone"). His wanting for her is almost animalistic, and he tries to warn her not to give in to him. But he also says it's partially her fault, for being nice to him and "letting him in with no intentions to keep" and tells her that being nice to him is a "kindness she can't afford" (I know the lyrics say avoid, but I'm pretty sure it's actually afford. At least that's what I always hear, AND also what the little booklet that comes with the album when you buy it says).
While I do see TKirby's point, I always felt like this song was about lust, rather than unrequired love. He portrays himself as a guy who wants a woman badly, and it surprises him, because he's not usually that way ("I know who I am when I'm alone"). His wanting for her is almost animalistic, and he tries to warn her not to give in to him. But he also says it's partially her fault, for being nice to him and "letting him in with no intentions to keep" and tells her that being nice to him is a "kindness she can't afford" (I know the lyrics say avoid, but I'm pretty sure it's actually afford. At least that's what I always hear, AND also what the little booklet that comes with the album when you buy it says).