Say that the grim reaper wanted you to trick someone into making themselves look bad, by lying about them to others, and says that you should do it by tricking them into looking crazy. If you don't do it, he says he would shorten your life by 50 years, and if you do, everyone will hate you for lying. Would you do it?
Personally I wouldn't. There are too many horrible aspects about life to want to make it worse for others.