Hahaha...I know what you mean. I believe that collectors always seek to make complete sets - to fill in that missing spot in the coin album so to speak - but the thrill of the chase is what makes it fun. Room keys and slot cards have a nice advantage for collectors as there's always something new coming out, some elusive variation that gets discovered, or some long ago issued card that we keep searching for and hoping to find. Making a "discovery", such as one emailed to me earlier today about a typo on a narrow Stratosphere key by a long-time collector, are fantastically exciting.
Sometimes I think we're a crazy bunch of people...but in a good way...which is why we all get along with each other so well
Jim