Nice post. I am another category...I borrow priceless objects from museums and collectors, learn about every millimeter of the object, I know the craftsmen, the materials, the stages it went through, sometimes I loving need to clean it and do things to protect it for the future, spend hundreds of hours in an intimate setting, I know more about it than my friends and relatives (sad to say)...alas then I have to give them back! Heart breaking when you know something so well and you never know if you will see your "old friends" again.
