Because you can recite the whole thing front to back, basically.
Because everybody — EVERYBODY — knows this line, even if you haven't seen the movie.
20th Century Fox
Because this license plate was spotted out in the wild.
MAWWIAGE.
Because Fezzik taught you the meaning of sportsmanship.
Fezzik: We face each other as God intended, sportsmanlike. No tricks, no weapons...skill against skill alone.
Westley: You mean you'll put down your rock and I'll put down my sword, and we'll try to kill each other like civilized people?
And he was an absolute master of sass.
Humperdinck: Surrender.
Westley: You mean you wish to surrender to me? Very well, I accept.