An interesting discussion came up on one of the agile groups I subscribe to; the Zeigarnik effect. What this theory says is that people remember unfinished tasks better than they remember finished tasks.
The context of the discussion was retrospectives. During a retrospective, people will be less likely to remember the tasks that completed smoothly in the project, things that fall under the category of what did we do well. Since these are important, you want to make sure people remember them.
One of the tools I use in retrospectives come from Norman Kerth's book. The tool is building a timeline of the project and having people identify key events throughout the project. This is one way to help people remember. Another technique is to hold your retrospectives often; at the end of the iteration rather than waiting until the end of the project.
As I was thinking about the Zeigarnik effect for this post, I also realized it impacts your work in progress (WIP) limits for Kanban. The more things you have in progress, the more things that you are trying to remember. Get your WIP to high, you start forgetting what you're supposed to be working on. So how much unfinished work are you trying to deal with?
On a side note, if you teach, you can use this effect to your advantage. Give your students an assignment right at the end of the day. They will keep thinking about it until they have time to finish it. They'll learn their lesson better than if they finished the assignment in class.