A quarrel with my roommate

Weeks ago,I had a quarrel with one of my roommates with whom I live in a small room. That day one of my roommates brought in a very large suitcase and placed it under her bed,but days later she found something wrong with her suitcase. As we live on the ground floor,her case soon got wet. She took it out and after drying it st put it on her desk because she had no other choice .I happened to be opposite her desk and her suitcase was so large that it not only occupied the whole of her desk but half of mine as well... I was so annoyed .Can you teach me some thing to keep me calm down? Thank you.