I s'pose we wouldn't become quite so jaded and need just the right monster to surprise players if ... well, if the players weren't so gosh-darned familiar with all the monsters already. Memorized stats of every single beastie in the book? Maybe not that excessive, true, but it doesn't take much study before the average gamer has soaked up everything he needs to ruin his own surprise.
I'm also in favor of Wombat's idea to limit the really smart critters populating the world.
I'm also in favor of Wombat's idea to limit the really smart critters populating the world.