Do military pilots have a phrase like "aviate, navigate, communicate"?
I am a Naval Aviator and have commanded a flight training squadron.  We actually teach that very phrase.  Aviate, navigate, communicate was one of the first things I learned, and it has served me well over the years.

It applies no matter the situation.  The target fixation example you gave is a good one.  Getting an aircraft where it needs to be to put a bomb on target is clearly in the navigate realm.  It is superseded by not flying into the ground...which is in the aviate realm.