used against someone who has just taken your obviously sarcastic statements
as an indication of what you actually believe. Has the effect of both stripping the easily offended jackass
of any perceived upper hand
in the argument and making him/her even more furious
that you had the audacity
to publicly declare their idiocy
All meaning that you, the sarcastic smartass, triumph again.
Bonus points if you point upward and actually get your victim to look at the sky before the punchline.