Throughout Jane Austen’s “Emma,” it is plain that the friendship between Emma and Harriet is less than ideal and more than a little selfish on Emma’s part. As Emma begins to lose her selfish satisfaction in the friendship and estimates Harriet’s virtues correctly, she also begins to more rightly estimate Mr. Knightley’s friendship and to respect his good judgment.
It would be overlooking the humanity of those in a similar position in real life to suggest that Harriet exists merely to serve the purpose of showing Emma what true friendship looks like. There is, perhaps, a more accurate observation.