An exclamation. Usually said when you're angry or surprised but don't know who to be angry or surprised at. (The Simpsons) Example: We have a pop quiz today?! I'm so mad at the secret service right now.
I'M SO MAD AT THE SECRET SERVI
Meaning of I'M SO MAD AT THE SECRET SERVI in English
Slang English vocab. Английский сленговый словарь. 2012