The drugs, to me, is their love. Mariah sings of a person wanting her first, hopping on the “drug” of love, and embarking on a relationship. As she begins to fall in love, they begin to fall out of love, or lose enough love to have had more when they first met. Mariah accepts that she gave them her all and is content with doing her part, loving them how she did, and no one else can. In all, you have to be okay with knowing your best may not be enough for some people and you gave your best to them anyways, regardless of what they gave you back in return.