We show love to others that might not deserve it, because when we do that it is showing them the Christ in us. Maybe one day they will realize that a caring person is difficult to find, and it will make them notice that you actually cared. But also when loving others that act rotten, it will bless you, because you did your part, now watch how that person will handle it. If their result is ungratefulness, then they shouldn't be surprised if you don't want to show your caring ways to them again. But at the end of the day, when you love them anyway, even after they've done wrong, the goodness in them should eventually come forth and appreciate you.