You see, when you open new doors, there is a price to pay. Now imagine... tonight, you look under your bed, and, lo and behold, you find a monster! And you're immediately eaten. Now, if you hadn't looked for the monster, you wouldn't have found it and you'd still be happy in your beds, instead of being slowly digested in the stomach sack of the creature. But, with any luck, your sister or your brothers might have heard your screams, and your endeavor will serve as a valuable lesson to them.
— Walter Bishop, "What Lies Below," Episode 2.13