Or the guy who says he wants the wheels you have as soon as you pull them off. You communicate several times, set a time for him to pick them up, then go out and swap wheels in the rain. Then you never hear from him again.
I also love when you have something for sale for $600 and say "$600 firm, I will not take any less, I am very firm" and the first email you get says "$150 cash" 
