overly sensitive sellers with lists of demands annoy me to no end, so when I sell a game I try to be as chill as possible. I don't get mad at lowball offers or ridiculous trade requests ect. I am not a huge fan of the "whats the lowest you'll go?" question though. I'd much rather have them make me an offer and then we can work it out from there. If somebody asks me whats the lowest I'd take, I usually answer with something that still gives me wiggle room. I imagine most people are the same way.
If somebody gives me a rediculous offer though I just tell them no thanks and move on as its highly unlikely we'll come to an agreement. I had one guy get really mad at me for this once though. "WHAT!? YOU'RE NOT EVEN GOING TO GIVE ME A COUNTER OFFER!?!???" Like no dude, you offered me less than half my asking price, so I think we're going to be too far apart. Then he goes on to tell me how he was actually willing to pay me MORE than my asking price, and that my game is a POS, and just all kinds of funny stuff.
Selling is always a fun time, I enjoy it.