It is in most people's nature to look for a deal. Having lived in the China I am certainly used to offering ridiculous prices straight off the bat, walking away, and waiting for the vendor to come running after me. If you pay full price there, after walking away, the shop keeper will spend the next half hour rubbing his hands together in glee.
It is not unheard of here now to try and get the price of something lowered, even in major stores, but there is no personal connection by the salesperson with the item being sold in stores.
Now you go to someone's home, the most personal of possessions. You automatically assume that the house is overpriced, even though your agent may tell you that they have looked around at the comps, and it seems to be within range. You can certainly afford the price listed. You love the house, but you cannot bring yourself to start with a reasonable offer.
You talk to your agent and tell them what you are willing to pay for the property, which is beyond reasonable. Your agent advises you that the offer would not be worth the paper upon which it is written, and you are going to insult the Seller. So you wait. You come back a few weeks later and decide to make an offer, a little higher than before, but still too low. This house has been sitting on the market for a while, so you are sure that the Seller is going to be more "reasonable". They are going to fall over and kiss your feet. But, as happens so many times, Murphy's Law of Homebuying kicks in. There is another offer being considered, all cash, and much higher than you were going to offer.
Had you made a reasonable offer when you first considered buying, and by "reasonable", I mean one that would encourage a counter offer, you may have been successful in buying the property you obviously love. Now, even if they look at your offer, chances are both offers will be bid up close to the asking price or over asking price.