Crazy threats that would end up benefiting the person you are threatening are always fun. This is generally a good reason not to make threats, because outside of bodily harm threats, how do you know what will and will not benefit them?
HOBO: Write a better paper.
AMANDA: Maybe I just won't turn in a paper next time!
HOBO: Then I'll fail you.
AMANDA: Maybe I'll just drop out of college! Then there will be no more paperwork killing the earth!
HOBO: Everybody wins.