What makes collecting celebrity autographs, vintage movie posters & historical documents so exciting?

Avid collectors have such passion about their particular areas of interest that is hard to imagine how anyone can NOT be a collector of something.  But, some areas of collecting can take on another dimension that goes beyond just another acquisition.  In the world of autograph and historical documents collecting, acquiring a significant historical document is truly a surreal experience.  For example, most of my family members are not collectors. However, when I first showed them a Presidential Appointment signed by Abraham Lincoln the excitement transcended to non-collectors.  I recall watching several “jaws drop” as they gazed at this magnificent piece of history.

Similar to this experience was when I posted a copy of a historical letter from Admiral Hyman Rickover discussing the recent loss of the USS Thresher. Now, to the average person there are no stimuli invoked by the mention of Admiral Rickover or the Thresher. HOWEVER, to a US Navy veteran, especially a veteran Navy Submariner, the hair stands up on the back of the neck as they read such a letter.  So, I recently posted this chilling letter to my 400 member submarine group and the response was what I expected.  Most of them were not collectors of autographs or historical documents, but this letter induced  special reflective memories. 
This is how the description reads on my web site:

“Even though I collect and sell rare historical memorabilia and documents, I have always maintained this in my own personal collection.  Fellow submariners can only imagine the horrific fate our brave young brothers endured.”  

So, here is an example of how non-collectors can relate to the passion of collectors