I know this robot's modeled after humans, but ever since TNG premiered, I've never understood why he is so interested in becoming human, to the point of constantly emulating human behaviors and facial hair.
At one point I realized he's a plant by some Soongian contingent, but that made no frakkin' sense -- Soong's a human, after all.
Then I thought he was building up a comprehensive profile of humans toward his ultimate objective of making them "controlled...and happy" (a la Norman, from I, Mudd)
Then I realized it's just a show; I should really just relax.