What makes Jean reprimand Kristine for insulting Julie, after the cook finds that her mistress has disgraced herself with the valet?
August Strindberg's play, Miss Julie, is a representative of the Naturalist movement, which is a part of the Romantic movement that deals with social survival and the portrayal of reality for what it is.
This being said, the characters that you find in a play of this genre are raw, driven by instinct, and quite flawed: Just like any typical person from everyday life.
In Miss Julie, the character of Jean is a servant in the household of Miss Julie, the daughter of a Count. In typical Naturalist fashion, Jean is far from a hero. First, he is chauvinistic. He freely insults both his fiancee Kristine as well as Miss Julie, his mistress, even after he and the latter had a sexual liaison.
Second, he is somewhat a bit of a loser: He talks a lot about becoming rich, about becoming an aristocrat, and about leaving behind the world of servitude. However, once he chooses to engage in illicit acts with his mistress, he suddenly fears to lose his job. He is obviously a man with big dreams, but little plans. This makes the reader categorize Jean as a man who contradicts himself, perhaps because he has no clue who he is, nor what he really wants.
For this reason, it is no wonder why he would tell Kristine that, despite of the fact that Jean himself is disrespectful to Miss Julie, she still has to remind herself of her place in the household.
Jean. [Sharply.] Be so kind as to speak more re- fined when you're talking of your mistress. Understand? Kristine. Mistress ? Jean. Yes. Kristine. No. I say, I say there Jean. Yes, listen to me. It is much better for you if you do, and don't gabble so much. Miss Julie is your mistress, and you ought to despise yourself for the same reason that you despise her.
Jean goes as far as to hint at the possibility that Kristine is not as prudish and virtuous as she claims to be. He blames her good disposition and her friendships with other males as conduits for indiscretion. However, it is only a way to throw a very cheap shot at Kristine.
Jean. Quite so. You had a little something on with a nice fellow, and very lucky for you, too. Kristine. A nice fellow, to be sure, who sells the Count's oats out of the stable. Jean. You're a nice one to talk ; you get commissions from the vegetable man and ain't above being squared by the butcher.
Therefore, Jeans behavior demonstrates that he is, in no way, a man that can be trusted nor admired. He is unsure of himself, of who he is, and of what he wants. For this reason, he lets his instinct- and his ignorance- rule his life. As a result, he takes his own self-doubt and indecision onto others, such as Kristine and Miss Julie.