Through your whole life, passion only is shown on your face when you wail and scream and cry. You need it to a certain extent because as Keating said, "the human race is filled with passion" and also that passion is the reason to stay alive, but just following your passions is not enough. You need to be able to control your passions and not let them control you. .
Another possible interpretation from a response I received is "Todd's poem, inspired by Whitmans picture, could be a symbol for the attempt to balance romanticism and rationalism. Truth being a blanket that only covers you partially always keeping your feet cold. The blanket is the attempt to balance rationalism and romanticism. No matter how you stretch it one way or the other something is exposed The feet are symbolising Todd's rationalism and the head represents his romanticism. As his rational side was the one that had always won out before that was the one most exposed to critcism, thus being cold. I would argue that Todd slowly throughout the movie began to movie the to cover more of his rational side and uncover some of his romantic side in an attempt to balance the two." .
Todd is the only one in this movie that understood this message that Keating was trying to teach. Neil let his passions take control of his life and it drove him to suicide. Nwanda let his passions get out of hand and it led to his expulsion. Knox also followed his passions and although he did get to be with Chris in the end, he sacrificed his relationship with his family and the Dansburry's. .
After Neil's death, Todd stares into the eyes of his madman. He first says, "It's beautiful," referring to the way that the blanket of truth (representing romanticism) is covering his face (representing realism). Then he starts crying and screaming, "It was his father." (This was Todd's first real experience with romanticism.) At this point he realizes his madman (passion) is mumbling truth, but it isn't enough.
