In the scrum world, we typically divide our stories in to bugs, features and chores. I find this classification limiting and that it does not address all the work that should be implemented to deliver an awesome product.
The problem here is not that any task cannot be classified into one of these categories. The problem is that these categories are typically owned by different people. The product mainly focus on features, QA focus on bugs and chores is a catch all, generally used to plan refactoring like tasks.
There is one group of people who have no place in these categories and they are the product end users. These are the little, little things through out the application which are neither features, nor bugs, nor chores but make a big impact on how the users perceive your product. I am calling these as 'Irritants'.
Irritants are those confusing messages, the non highlighted action button, the convoluted menu structure, the UI redundancy or lack of it and all those little things which make using the product that much more painful.
I find products filled with irritants all along everyday. Some of our most popular products today will disappear in the months and years to come mainly because of their failure to address this key story type. We focus on pixel perfect designs, micro second load times and debate on using Java vs PHP, but what really will delight our users I believe is removing these 'Irritants'.