So a lady walks into a bar on the 20th floor of a building. She starts drinking and a man walks up to her and says "Do you want to watch me fly?" and she thinks 'what a creep' and ignores him.
So a few hours pass and no one has talked to her so she goes back to the guy and says "Ok, lets see you fly." So he takes out a flask and drinks from it, jumps out the window and starts flying, then comes back.
She says "Wow do that again!" because she is so amazed. So he takes a swig from the flask and flys again.
When he comes back she asks "Can I try?", she takes a swig jumps out of the window and falls 20 storys to her death, then the bar tender looks at the man and says "You know superman, your a real asshole when you do that."