I'm thinking of shredding my roommate's essay while he sleeps
Why would you do that when you know that he worked so hard on it?
Come on, I don't think he worked that hard on it.
If you shred your roommate's essay, he'll have to rewrite it and you'll be violating his trust. It's wrong to shred someone's property, but it's particularly heinous to shred something that represents hours of hard work. Be respectful of your roommate's things.
Good, now he'll have to do a better job on his next essay.
That is not the way to look at this though. You should not destroy his work when you know what is at stake. You would be so upset if he shredded up your essay.