Quoted from LTG:

1 - tire kicker
2 - keeps asking questions
3 - keeps asking for more pictures
4 - tells what they go for on Ebay
5 - tells what they can buy a better one for
6 - makes ridiculous requests like can you hold it for a month, until wife sees it, until Haley's comet returns
7 - makes ridiculous offer
8 - wants to think on it
9 - asks to see other games you aren't selling
10 - wants to play your other games ignores purchasing the one they came to see ( you aren't running a free arcade )
11 - Then there is the person that makes a reasonable offer or accepts your price in cash and can pick up within an hour.
After time you'll spot the #11 scale people quicker.
LTG : )

Quoted from jawjaw:

I've encountered sellers that are not really selling. I also love sellers that immediately take a long vacation right after posting. Others like some mentioned here act like it's a huge bother to answer a few questions or send a few extra pics.