Most of the deals I've completed on craigslist conclude with a brief conversation about how nice most people are to deal with. The serious buyers and sellers always have a few minutes to chat, even if you're just meeting up at a Starbucks or 7-11. The people in a hurry make you feel like they are scammers or antisocial.
I discard most emails that lowball, and only deal with serious adults that aren't afraid to follow up on their word.
You know I agree - every actual transaction that I've been party to on CL, usually spend a good 10-15 minutes talking to the person before/after the fact - in person. It's sad that out of maybe 20 emails on any given listing, about 8 are nigerian scammers, 10 are lowball/trade offers, and there's maybe 2 that are legitimate offers.
