don't understand that overpricing can actually result in your getting LESS for your house than if you had priced it correctly in the first place. Knowledgeable agents and buyers often won't bid on an overpriced home. By the time you "wise up" and reduce the price to where it should have been priced in the first place, many of your best prospects will have bought other houses. This decreases demand for your now properly priced home! The problem is exacerbated if you placed your home on the market in the spring, it sat on the market "overpriced" throughout the summer, and now that you've reduced your price, the market has slowed.
Also, consider that agents tend to steer buyers away from homes that have been in the Multiple Listing Service for long periods of time. Agents and buyers become suspicious that something is wrong with your property if it didn't sell relatively soon after it went on the market. It's important to price it right the day you put it on the market!
Also, consider what you could have done with the profits from the sale of your home if you had priced it right. Suppose you priced it right and sold relatively quickly, and invested that money in a rising stock or bond market. On the other hand, suppose you overpriced your home, and after several months, had to reduce it to where it should have been priced in the first place. Even worse, the house still isn't sold!