An amateur insult comeback. It is often regarded as one of the worst possible insult comebacks, being criticized for its lack of creativity, low versatility, and manipulation of English grammar in the word "you."
The comeback was popularized by a scene from the 1985 film 'Pee-Wee's Big Adventure,' in which Pee-Wee Herman repeatedly says the comeback after being told a string of insults by someone else.
The comeback was popularized by a scene from the 1985 film 'Pee-Wee's Big Adventure,' in which Pee-Wee Herman repeatedly says the comeback after being told a string of insults by someone else.
Mark: You should have let me copy your test answers in class today.
Jim: No, it's against the rules. Stop relying on me to bail you out all the time. You're such a blowhard sometimes...
Mark: Oh, yeah? Well, you're a coffee whore whose father is on crack!
Jim: I know you are, but what am I?
Mark: You're a loser who doesn't let me copy your test answers in class!
Jim: I know you are, but what am I?
Mark: -_- seriously dude
Jim: No, it's against the rules. Stop relying on me to bail you out all the time. You're such a blowhard sometimes...
Mark: Oh, yeah? Well, you're a coffee whore whose father is on crack!
Jim: I know you are, but what am I?
Mark: You're a loser who doesn't let me copy your test answers in class!
Jim: I know you are, but what am I?
Mark: -_- seriously dude
by A Person Named September 7, 2013
Get the I know you are, but what am I?mug. by Oh crackers April 26, 2019
Get the I know you are but what am Imug. by BANANASSSSS_ARE_NOT_YUMMY_HAI January 15, 2017
Get the what am i supposed to type here?mug. 
A moment of sudden realisation. Derived from the feeling felt when one is home alone and realises that the act of wearing pants is futile.
Man, I just had a "Why am I wearing pants?" moment: Edward Norton's character didn't have a name for the whole movie!
by Sean92 April 30, 2009
Get the "Why am I wearing pants?" momentmug. “What am I doing with my life?”
by Just a guy who’s really bored January 25, 2019
Get the What am I doing with my lifemug. A complete fail of a comeback... basicaly... you would use it when you get verbally bitch slapped your face is all red... and you cannot come up with a comeback.
Faggot: You smell bad
Me: Wow... because you said that dis you went from nobody loving you... to having a small squirl start to love you... oh wait... that squirl just got ran over by a car... your back to nobody loving you...
Faggot: I know you are but what am I?
Me: Wow... because you said that dis you went from nobody loving you... to having a small squirl start to love you... oh wait... that squirl just got ran over by a car... your back to nobody loving you...
Faggot: I know you are but what am I?
by balla911 April 16, 2009
Get the I know you are but what am I?mug.