Science Question: Why does the toilet paper sometimes tear along a line other than the perforated one?

(Doesn't this mean that somehow the "perforation line" that separates the individual sections of the toilet somehow mysteriously "add strength" to the paper itself, given the fact that when you tore it off, it deviated from the pre-perforated path? That's kind of spooky if you think about it...*nodding head and very frightened now*)