Wanna know how I got my revenge on my roommate a few years ago?
Yes, how did that happen?
When he was busy with plans for a trip with a group of friends, I stole a few dollars from out of his pockets.
While you may have been annoyed with your roommate, what you did is considered stealing and is actually illegal. It's not smart to try and get revenge on people by doing illegal acts, and you should never take something that isn't your own.
This is actually my last day here. I am not even going to see my roommate after this.
If it's truly your final day, why not try to confess to your roommate and make up to atone for what crime you did? He may be disappointed, but still relieved you told him in the end. That will show you are willing to change.