That's My Secret
A meme that uses the Incredible Hulk as its inspiration. A popular one at Reddit at the moment.
Taken from the motion picture, "The Avengers", it features The Hulk's alter ego, Dr. Bruce Banner, at one of the classic moments in the movie, saying "That's my secret - I'm always angry"
It's an iconic moment, and the standard text of this macro is the line "That's my secret" at the top.