Read the Fucking Manual, Asshole.
But you can't call an officer "asshole," so in the military RTFMA stands for "Read the Furnished Materials, _Sir_."
"Corporal, how do I order blankets for the new transfers on this stupid computer?"
Clerk, handing the First Looey a pamphlet: RTFMA.
Clerk: It's right there in the manual, sir.