Personally I think it has a lot to do with a person's listing and how they carry themselves during communication. It's pretty obvious the kind of deal you can expect out of a guy by how he carries himself on his listing or communication after contact.
Some guys are willing to be patient, answer any questions you might have, send pictures, whatever you want. These are the guys you want to deal with.
Some guys don't feel like answering questions, won't post or send pictures, publicly act like jerks when asked things about their items, are incomplete with their answers about their items like "it appears to be, I think it's, Google it...." essentially they are just plain arrogant and think they are above you.
It's bummer when you encounter guys like that. I always try to refer to the golden rule. Otherwise karma kinda sucks.