Like everyone else here, I hate making offers. Especially, as Klet mentioned,
when the seller says something like "I paid a lot for my cels so don't waste
my time with low-ball offers." Um, yeah. Huge turn off. I don't know what
other collectors consider a lot or a little. I've gotten some extremely rare cels
for low prices (just lucky I guess, I don't know). But the value of the cel
shouldn't entirely be based on what YOU paid for it at the time. Things change.
Markets and interests evolve. Something that was $600 a few years ago may
not be worth much now (just look at VHD Bloodlust cels. From some sources,
you can get them dirt cheap).
Off the top of my head, I can recall two offers I made on cels I now own.
I overshot on both. One was MUST have, the other was not so much.
I also actively bother people who have cels I want

I can't help it. You
never know when someone might consider parting with said item. I prefer
a bit of back and forth with the communication when striking a deal. Let
the seller set their ideal price and I'll let them know what I'm capable of
doing. Be it a lower price or a more liberal payment plan, etc. I've acquired
several cels via these methods.
I do get extremely ticked off by people who get all pissy about "low offers"
or emails asking about their cels. If those emails
really irritate you,
then don't display your cels online. And please don't assume everyone has
your standard of value. I have no clue what you paid for your cels. For
all I know, you might be some bid-happy nut who hates money.
If someone emails you about your cel, consider it a compliment. I still
can't figure out why such emails incite violent and venom laden reactions
from the owners. Can someone please explain this to me?
Perhaps, if the emails bother you, just put up some hideously bitchy
warning on your gallery to scare folks away from making unrequested offers.
I've considered it a compliment every time someone has taken the time to
contact me about my cels. Like Sugarflower, I reply to everyone with the
kind of respect I'd appreciate receiving. Being polite isn't difficult and takes
just a few seconds of your time to simply say: "Thank you, but no."
Unanswered emails (if they are blatantly ignored by the receiver) are
rude and in poor taste.
I think all of these reasons are probably why people are uneasy about
making offers or even expressing interest in other collectors' cels.