Boy was my face red when I started reading 
through this post that my wife started. Long 
story short, the offer/counter-offer process went 
less-than smoothly for a number of different 
reasons, my harsh response to the initial offer 
being one of them. By harsh, I mean that I spoke 
my mind and said the offer was "insulting." I did 
try to explain why I felt the offer didn't meet 
our expectations, adding what my wife had paid 
for the cel and comparing some other cels of a 
similar variety that have come and gone. As we 
still weren't on the same wavelength, I 
apologized (and apologize again) for the 
harshness of my initial response and kindly 
suggested that we leave things as is: the cel in 
our collection and the money in the interested 
party's pocket. I agree wholeheartedly with all 
here who have stated that it's bad to fly off the 
handle at a "low" offer, however I also believe 
that if you want to pry a cel from someone's 
collection you should at least try to be as 
polite as possible. This individual was, IMHO, 
not. After all, the cel (or whatever) is in the 
person's collection for a reason. Then again, my 
reaction was a little less than polite, too. 
Another lesson learned on my part :)