In software design and usability, it’s the little things that make a difference. (For example, see this post on two secrets of Mac design.) Sometimes the little things aren’t good, however, as I discovered with GMail today.
I was processing through my contacts and deleting those I don’t want. I spent a while selecting all 123 contacts to delete and hit the delete key, only to receive this message:

When writing this function of the GMail interface, the developers should have considered that people would probably want to batch delete their contacts. I specifically selected all of them to save time, rather than going through in little groups like I evidently should have.
It might seem picky, but this is the sort of thing that differentiates good software from great software.