On the other side of the fence, a company that interviews a candidate and waits more than two weeks to make a decision is essentially saying good-bye. It is often difficult for a company to bring in all of its candidates in a short time, but in this job market companies must act quickly and assertively, if possible within 48 hours of the interview. If the company waits, the candidate can be exposed to new opportunities. In addition, the candidate's enthusiasm after the interview will fade to some extent. Companies that can't come close to meeting someone's salary demands sometimes read the candidate a laundry list of his shortcomings to justify a lower salary.
People do some strange things when they're trying to make a good impression.
Another bad idea is intentionally lowballing on the first offer knowing well it will not be acceptable. The only thing this does is to create a confrontational negotiation from the get-go. Money can do strange things. A company's choice for a job asked for more money first. When the company said yes, he turned down the job after all.