Are people on drugs??

My brother responded to a Craigslist add for a camper, he had to email the guy a dozen times just to get a phone number, the guy tells him he can't figure out why he hasn't had any more calls on it. If I am selling something especially online, I make sure to check my email and cell phone multiple time a day.
It's not only sellers that are idiots, some buyers can be idiots too. I listed a scooter on Craigslist, one guy called telling me that it had a lot of miles and that he would give me half my asking price and that he was looking at one with half the miles for the same price(well then you better buy it). Calls back a couple weeks later, and berates me when I say I am on vacation and am out of the state and won't be back for 4 days.