Why does this girl give me a dirty look?

She sounds jealous and slutty. But, there could be another side to the story. Maybe she has issues with her family or problems with self-esteem. You could try and talk to her in a nice way about it. Like, "Hey, I don't think we have ever really talked." or "Hi there." If she's just a plain ***** just gave her a snappy rebuttal if she says crap about you again. She says you look ugly in a jacket, turn around and say "Why the hell are you even looking at me? Your eyes are no worth my awesomeness!" or better yet just say some totally out there thing like, "Dude, my jacket may be ugly to you but it wasn't made of kittens. So it's all good." She gives a dirty look star right back at her until she looks away. If she doesn't look away and says something rude like "What are you staring at?" say you were staring at the green thing in her teeth or the black dot on her forehead.Sometimes getting out of your comfort zone to put a ***** in her place is a good thing and worth it. But if you are just against drama then kill her with kindness. Then you''ll be an angel and she'll be a ***** for being mean to you any other time.