M.A.S.H. made an indelible impression on me. My Dad - who was a very conservative Republican, and fully supportive of Richard Nixon's policies in Vietnam - for some reason decided that our family should go see the film when it hit our local theater. At the time, I was astonished, because the film sent very clear messages about the pointlessness and stupidity of the Korean war, and by implication the Vietnam war. In retrospect (from 50 years later), I can see how it would interest my Dad; he was a WWII vet (8th Army Air Corps), and an M.D.
M.A.S.H. (the movie) contributed to my political maturation, because it really did crystallize how stupid a nation's policy choices can be. My Dad... well, he never did abandon his conservatism, notwithstanding the messages of things like M.A.S.H. In fairness, he wasn't immersed in political theory or practice the way I subsequently was, and his interest in military history was focused on the Civil War (a result of growing up in proximity to Gettysburg, I think), as opposed to more broad-brush military and/or political history.