A fork of Rural Dictionary
An acronym meaning: Shoot me in the Fuckin' Face.
A variation of FML.
Used mostly in text messaging to convey complete and utter annoyance.
First Person: "I have 7 tests and a paper this week"
Second Person: "Wow, That's rough"
First Person: "I know just SMIFF"
or
There's so many annoying people here today. SMIFF