The instant I read your question, I immediately thought of Dennis Hopper in Blue Velvet. The profanity was constant, violent, and oddly horrible in its intensity. I mention it because it truly disturbed me, while most profanity in films seems merely banal, or typical. Hopper with that creepy nitrous mask saying, "Baby wants to f*ck!" Ewww! And juxtaposed with Isabella's timelessly gorgeous face, it was beyond strange. (She reminds me of the bust of Nefertiti in Berlin, sort of a beauty beyond beauty.) I rather think David out-Lynched himself with that one.
You've got a point there. On the other hand, to me the most memorable profanity in BLUE VELVET was "Heineken! F--- that sh--! Pabst Blue Ribbon!", a line that my friends and I repeated endlessly throughout college. This comic relief line, which comes at a point of almost unbearable tension when Jeffery is helpless completely within Frank's control, really sticks in the mind.
