Could Su Xiaowan not be angry? Perhaps being deprived of things since childhood had left her with lasting shadows, she was simply repulsed when someone touched her stuff without her permission.
Furthermore, their relationship was just casual, and this infringement felt like a personal violation.
This was hard for her to bear; for some reason, the thought of Yan Hong having touched her sheets disgusted her. She didn't want to use them anymore.
Once her personal items were tainted, they were of no use to her or anyone else. Despite being called pretentious or melodramatic, she couldn't care less.
However, had she been unable to afford food, she probably wouldn't have acted this way, but Su Xiaowan was quite fortunate. So what if a set of sheets was ruined? The main thing was her peace of mind.