You need to internalize a desire to use the finished product. In otherwords, you have to want the finished product. This is probably a horrible misquote, but

You need to internalize a desire to use the finished product. In otherwords, you have to want the finished product. This is probably a horrible misquote, but I remember a long time ago John Caramack saying that what drove him to fix all those little stupid bugs at the end of a product was the desire to play the finished game. Others who just wanted to ship it were having a tough time sticking with it since they just liked developing cool tech and wanted to move on to the exploratory phase of the next project. Now, if it's a clients website you have absolutely no interest in and can't figure out a way to have an interest in (coding for it's own sake), you've got bigger problems :)