When I first started out in engineering, people would talk disparagingly about somebody being a "ninety-five percent" guy. I had one for a boss. He would assign you a partially complete task saying it was ninety-five percent complete. You just had to do the five percent that took ninety-five percent of the time.
In Agile development, a task or story gets no credit until it's completely done. This is an important concept. Done is often a lot farther than it looks. A developer may write a bit of code that compiles and seems to work. He may think he's done, but he's not done-done. The team needs do develop a working agreement of what done-done means.
Here are some articles on the topic:
Artem Marchenko's [http://agilesoftwaredevelopment.com/2006/05/definition-of-done Definition of 'Done'] discusses the need for such a definition and what it might include.
Michael Nygard's [http://www.michaelnygard.com/blog/2007/11/a_dozen_levels_of_done.html A Dozen Levels of Done] has another such list.
Chris Sterling's [http://chrissterling.gettingagile.com/2007/10/05/building-a-definition-of-done/ Building a Definition of Done] describes a story of un-Doneness, and talks about a method to decide on your team's definition.
Payson Hall's [http://www.stickyminds.com/sitewide.asp?Function=edetail&ObjectType=COL&ObjectId=10476 Done and DONE-done] points out that without a definition of done, you don't get done.
Jeremy D. Miller's [http://codebetter.com/blogs/jeremy.miller/archive/2006/04/13/142800.aspx "Code Complete" is a lie, "Done, done, done" is the truth] describes how less than Done-Done is pretty worthless.
Aaron Ruhnow's [http://www.scrumalliance.org/articles/37-are-we-there-yet Are We There Yet?] lists his team's definition of Done.
Derik Whittaker's [http://devlicio.us/blogs/derik_whittaker/archive/2007/05/12/definition-of-done.aspx Definition of 'Done'] offers another definition of Done.
Michael "Braidy Tester" Hunter's [http://www.ddj.com/blog/debugblog/archives/2007/05/you_are_not_don_30.html You Are Not Done Yet: Developer Edition] offers a tester's list of things a developer might forget to test.
Does your team have a working agreement of what Done means?