brain surgery
A task requiring extreme intelligence, skill, or competence, usually used in a negative or rhetorical manner to indicate the opposite. Just follow the directions as they're written—it isn't brain surgery.
meatball surgery
Battlefield surgery that is performed hastily so as to quickly stabilize a patient and prevent his or her imminent death. Popularized (and possibly coined) by H. Richard Hornberger in his semi-autobiographical novel M*A*S*H, which focused on doctors serving in a fictional mobile army surgical hospital during the Korean War. Primarily heard in US. At the height of the conflict, our surgeons were primarily concerned with meatball surgery, getting wounded soldiers patched up long enough to receive more specialized treatment down the line.