Constant vigilance is the price you pay for an elegant application.

This means you have to learn to say no. Your current customers will ask you for a feature they want. Potential customers will tell you that if you add just one specific feature, they’ll buy the app. You can’t be everything for everyone. You have to let some people be customers of your competitors.

For an example of software where no one has ever said “no” to a customer, look no further than Microsoft Office. From later in the post:

If you leave features in your application just because half a dozen people actually use them, you’ll end up with Microsoft Word. Most people only use a small percentage of all features in Word. Unfortunately, most people use a different small percentage of all features in Word. Even the most unpopular, most broken feature is used by somebody. Nadyne Richmond, a user experience researcher in the Macintosh Business Unit at Microsoft, explains it like this:

There are people who insist that Word 5.1 was the pinnacle of word processors, and everything that has been done since then has been nothing more than bloat. They tell us that we should update it to run under OS X (and now they want it as a Universal Binary). Oh, but while we’re in there updating the code, could we please add their ten favourite features? As the ever-insightful Rick [Schaut] points out, ‘by the time you add up all the «Plus’s» you come to something that’s not all that far away from Word 2004, which is how we got here in the first place’.

Presumably, somebody needed Word 5.1 «Plus Web Search», so Microsoft went ahead and added the feature.