In my mind, I probably took this too literally. Suppose only half the keys you pressed actual put a letter into the document, etc. It'd be far less useful. The

In my mind, I probably took this too literally. Suppose only half the keys you pressed actual put a letter into the document, etc. It'd be far less useful. The 80-20 rule applies to software: 20% of the feature set is used 80% of the time. Mid-way through development, it's likely the 20% may not be complete. It was a poor analogy.