I'm going to spilt gin all over my friend in a lesson then not say anything as the teacher notices
Why would you want to be so mean to him?
Yes, for some petty reason I do it. And I have no reason behind it
You shouldn't try to be getting your friends in trouble. They'd be really upset.
What does it matter as long as I'm having amusement.
Your friend is going to feel so betrayed by you. It is bad to get your friend in trouble for your own amusement.