How Do You Deal with Abnoxious People?

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I had gone on leave in June and I left this girl to sit for me and after I came back she requested the boss if she can continue coming to use her laptop in the office and he agreed. We were getting along great until I requested her to allow me to clean the office on a Friday and she was not ready to leave yet even though it was already 5pm and that is when she got so angry and walked off. When she comes to the office, she talks on her cell phone so loudly and leaves the kitchen a mess for me to clean after she is done using it. How do i relate with her knowing that she is not even a colleague for me stress over but a guest of my boss and she feels that she is entitled?