recently rewatched TNG ep Time Squared
, the duplicate Picard lying on bed in sickbay and looking around in horror and confusion. Very creepy, as I dreaded the moment he would be looking straight into the camera (didn't happen, btw).
Then again, I suppose it was intended as such.
add: one which is definitely not intended as creepy but does give me the creeps in retrospect (of DS9 and such):
[Wesley]: We're from Starfleet, we don't lie!