The Baby Carriage Scene

Genius how dePalma gets the viewer's stress levels up with the crying of the baby - a natural human emotion is triggered by that grating sound.
Then when the baby starts rolling down the stairs, we see the Mom yell "MY BABY!" but there is no audio for us to hear it - it is muted, but yet the viewer is screaming it for her in our minds.
And then the pram gets shot, and he doesn't let us off the hook until the end of the scene, when we finally see the baby is OK.
I saw it in a 100 yr old theatre in my town tonight. There were almost 200 people there. I was surprised by the turnout.