ANY hobby can be addicting.  When I was a kid, I 
was mildly interested in electric train sets.  
When I'd go to the store with my dad, we'd meet 
all sorts of adult men who were fixated on their 
basement layouts and spent every last penny on a 
new locomotive or piece of track or background 
element.  One guy even set up his layout in his 
living room (on a giant table that took up 85% of 
the space).  His wife was ---NOT--- happy.  ;-)

Specifically with cels, though, this can be 
magnified because not only is this an addictive 
hobby but the items we collect are UNIQUE.  Sure 
there are sequence mates, but you know that there 
are absolutely no other production cels in 
existence that are exactly like your cel.  That's 
what makes this hobby wonderful....and dreadful at 
times.

And even though it doesn't affect the vast 
majority of people I've met via this hobby, we all 
know there are otaku out there who define their 
existence by their "uniqueness".  Be it their 
unique knowledge of obscure anime/Japanese trivia, 
their unique cel/shitajiki/doujinshi/etc 
collection, or even their unique odor. (LOL!!!)  
These are the folks who, for one reason or 
another, couldn't cut it in "the real world" and 
have retreated into anime as an escape.  And for 
them, these items take on far too much 
significance.

Finally, I find that the people who shout:

"Not Selling!  Don't Even Ask!" or "Never 
selling even if I'm on death's door, will be 
buried with these cels"

are the same people who will:
A) Decide one day to "quit" cel collecting and 
dump all of these "priceless treasures" for cheap 
or
B) Will have a fire sale to pay off the HUGE, 
ONCE-IN-A-LIFETIME WISHLIST cel they just found!! 
 (And then, a little later, they will sell that 
cel for the next wishlist cel....lather, rinse, 
repeat ad nauseum.)

Passion in this hobby, more than in others I've 
participated in, seems to go hand in hand with 
fickleness.  The people I know with the best cels 
seem rather laid back about them because they seem 
to know that if this one or that one gets 
away....another will eventually come along that's 
just as nice or better.  :-)

JP