Why does maggie slam the door when dee asks for the quilt?

Maggie is tired of Dee asking for things that she (Maggie) will use everyday. Although Maggie cannot articulate her frustrations she still feels them intensely. Maggie feels the flippant condescending tone in Dee's voice. She belittled in her sister's presence. Maggie feels that her only way of voicing her dissent is by slamming a door.