One of the hardest things for any software designer to do is to decide not to implement a feature. Many software projects have been delayed or even derailed by feature creep, or the tendency to widen the scope of a project during development. But in many cases, features that seem like "must-haves" during development can be deferred to later phases of development, or cut completely. Perhaps the paradigmatic example of this is the original iPhone OS's lack of cut, copy and paste. How could Apple have omitted such vital features? It didn't seem to hurt sales of the iPhone though.
Today I just ran into another example, also from Apple. In Xcode, you can switch from a header file to its corresponding implementation file (and back) using the keyboard shortcut Command-Control-Arrow (any arrow). This is a really nice way of navigating back and forth while you're creating new instance variables and methods for your classes. However, when you navigate in this way, the project browser at the left doesn't update its highlight to indicate that you're viewing a different file. Is this a bug? Probably not. It's probably just the designers of Xcode deciding to rein in feature creep so that they can actually ship the product.
It's so damn tempting to want to make sure every little bug is fixed and every little corner case is accounted for before you release your software. But, as they say, perfect is the enemy of the good. It's crucial to know when something is good enough so you can ship it as soon as possible. With cut, copy, and paste, Apple finally introduced the feature into its third version of the iPhone's operating system. By then they had already sold millions of phones to customers who decided they could live without that crucial feature.