Because to confide a part of your soul to something that can think and move for itself is obviously a very risky business.
J. K. RowlingGeorge: "I can't see anyone trying to bump off a quidditch team." Fred: "Wood might've done the Slytherins if he could've got away with it.
J. K. RowlingPagford, which by night was no more than a cluster of twinkling lights in a dark hollow far below, was emerging into chilly sunlight.
J. K. Rowling