Roommate Issues Dream

I had a dream last night about my current roommate who has two kids that I love to death but when it comes time to study just wish they would give me my space.
So in the dream it started out my friend and I were going shopping and I am aware of her money issues at this point in time and she had asked me to help her avoid spending excessively. We went in a store with miscellaneous items and it seemed as though the owners of the store were friends we both knew and wanted to support. My roommate and I had our things at the cash register. She had a large pile of things and I had a small pile (what I thought to be just a few things to support our store owner friends). We were still picking things out when She found 3 purses of the same design. The only difference in the purses were the colors. I specifically remember that there were a large style and a smaller style. She decided on getting all three of the smaller styles, originally $200.00 but on sale for $64.95 each purse. I simply whispered to her that she didn't need all three of them trying to follow what she had asked me to do earlier by keeping her from buying too much. She immediately blew up on me and stormed out of the store. I saw her standing through a glass window/door of the store calling one of her friends. I could vaguely hear her yelling and cursing about how mad she was at me for bringing up her money issues. She looks up at me with the phone held to her right ear glaring at me. I became upset by the way she was handling this situation and proceeded to point directly at her to maintain her attention and mouth the words "**** you" and walked off to the car or my apartment or somewhere. During the trek, I remember her following close behind me picking up small stones on the side of the pathway and throwing them at me. I continued to walk ignoring her and finally got away and that is when my boyfriend came into the dream.
I have recently become frustrated with my roommate about some small things but why would I have a dream where we both become completely enraged with eachother over such small things?