Like when uttering disbelief at something that happened.
Usually said by crazy people, who imprint it onto the minds of those less fortunate
e.g
Beth-checks out Not very fit guy
Rosie- "as if you just checked out that guy, LOL"
Beth- "one day im going to start saying as if"
--------
Beth- "As if sir just made fun of us"
Rosie- "aha i know"
Beth-"holy shit, i said as if"
"You know how lottery winners always say it won't change their lives? Yeah, as if!"
You know how lottery winners constantly claim that it won't impact their lives? Yes, as if!