I think the issue boils down to people wanting all the take and none of the give.
Whether it's pricing their listings too high, or expecting daft discounts on things they're interested in. How many times have you tried to sell something, you get an offer, you say it's less than you want but there is a deal to be made, then they make out your product is shite and worth pennies to begin with. "I didn't want your number anyway" type nonsense.
We're all adults, it shouldn't be too hard to be reasonable both when selling or buying, but still some people make that seem impossible. The Airsoft community has a lot of great people in it, we should treat each other with basic courtesy at least!
*Alexa, play Earth Song by Michael Jackson*