Why Did I Do This?

So yesterday, I decided to play a prank on my roommate by switching out her toothpaste for one of those cinnamon flavored ones. She hates spicy foods and never buys anything with a strong taste. Yet, here I am, lying awake at night wondering why I felt the need to do something so petty and childish. Was it really just boredom or did I have deeper issues with wanting to mess with someone's routine? It's not like my roommate has ever done anything to me, but sometimes these impulses are hard to resist. Now, I'm left feeling guilty and slightly relieved that she hasn't noticed yet.