I have not even seen one movie that was nominated for best picture. Don't care if it wins 20 awards.
It does affect your viewing. I just saw Pan's Labrynth not long ago and it is indeed a very good movie. Beautiful, tragic, hypnotic, mesmerizing, all that. But you can't help but notice that the fascists are the bad guys (well, yes, they are) and the communists are the good, noble, selfless, brave heroes (now wait a minute.)
And once you are awake to manipulation, you can never fall asleep again. In Pan's Labrynth, when the bad guys kill off the wounded after a battle, you see it. They put the gun to someone's head and BANG! you flinch as they execute victim after victim.
But a half hour later, when another skirmish ends with the communists in possession of the field, the same thing happens. The winners go around and polish off the wounded, but the camera lifts up to the sky, slowly panning across the leaves as if sighing with relief... little things like that, you notice.