I think part of it is the chance that you may 
have to sell your cels later.

OR the idea, that "what if I see another cel 
later that is comparable and I overpaid with 
the first one?"

so... people then want a way to grade cels, so 
that when they see one they can say "oh well... 
its worth it becuase blah blah, and the market 
says this character is rare, and this is an "A" 
shot"

whereas... a far off, backview of a character, it 
would be harder to pay alot for , becuase, they 
usually are priced lower, so even though I may 
ADORE this cel, I'd probably feel foolish 
paying the same that I would pay for a facing 
front closeup shot.

I'm talking more about your comparing the 
cels you buy to other cels from the same 
scene or series that come up later. and then 
feeling either good or bad about your 
purchase...

unless you just stop shopping, its hard to not 
reevaluate your purchases. like "wow, i really 
got a deal on that one" or "hrm, I kinda 
overpaid... if I had to sell this I would probably 
have to take a loss" (not that I ever WANT to 
sell my cels, but sometimes you have to)

course if I had gotten that totoro, I dont think I 
would have worried about it, even if I had 
overpaid. :# some things truely have no 
monetary price. perhaps one day I'll see one 
again and I'll be better financially endowed. -_-