Thea Queen as played by Willa Holland is perhaps the most dynamic character that Arrow has ever had. Oliver Queen, over the course of the show's many season has become a bit stale and so his little sister is really the one that had the most complete and satisfying arc. Thea Queen, in the first season looks to be the basic conception of a teenage party girl sister and someone to be easily looked over. So when she returns later on as a full fledged dark avenger, it is the most shocking and exciting development that could have been created for the character. From the first season's prep school pleated skirts and low cut party dresses to the business like blazers she wears when not in her superhero alter ego, the change in her character's look is noticeable. The hacked off hair serves to make her look older and more respectable and we can't get enough of her comic book costume. The all red, leather get-up is in direct contrast to her brother's darker attire and serves to set her apart from Oliver Queen. Which is perfect because this is a character who deserved to be appreciated in her own right.
She was my sister. I couldn't be angry because she was dead. I couldn't grieve because I was so angry, that's what happens when your sister dies while screwing your boyfriend.