Lady Despina felt that her roommate was not considerate and that he did things that she felt were not ok. When he did not change even after her talking about it several times, she had to act and she did it by destroying and crushing his stuff too. She did that to his art stuff and he got to feel how she felt when he did the things he did.
Lady Despina was angry at how this girl had lied to her and so she took her watch and she crushed it and destroyed it. She knew how expensive the watch was and that was why she chose to get back at her that way. It was a prized possession but it was now no longer there thanks to her lying ways. And it was a huge lesson to her.
Lady Despina wanted to show this guy what she really felt about flowers. It is not every girl who likes flowers and this guy made that mistake and that assumption. The mistress took his flowers and she cut them with a scissor and then she used her high heels to crush him. The mistress laughed at how shocked he was. She told him she had no problem with him but she was sending a message that she hated flowers.