Why do some homes sell quickly while others languish on the market indefinitely?

Last week, the house I  listed, was sold the first day for top dollar...This is not the typical experience for most sellers. About 20% of homes never sell.  Those that do sell fall into various price points...some sell quickly and for more money and the rest slowly and for less money. Why? 

The two factors that help predict the outcome in the sale of a home are price and presentation.  But, this in itself is not the whole story.  A good realtor has an understanding of the psychology of  the buying process; and what separates the 'solds' from the still 'listed' homes and the homes that sell for top dollar from the homes that sell at the lower end of the price range.  

Since a 'buying decision' is motivated by emotion, sellers must help  'buyers' fall in love with their home. If this is successfully done, the next step is to ensure that the home is well priced.