"What’s the most ignored paradox in software development? Every time you add something you take something away.
Screen real estate. Interface clarity. Simplified testing. Shorter development time. Certainty. Agility. Managability. Familiarity. Adding anything dilutes everything else. That’s not always a bad thing, just be aware of it. Be aware of the trade-offs.
The dilution effect is why maintaining a clear vision for your product is so important. Without a clear understanding of the limits and boundaries of your product, the product will morph into something you no longer recognize. Or worse, something you can no longer manage or control.
Jason Fried, "Every time you add something you take something away," Signal vs. Noise, 37signals.com, 4 Mar 2006, www.37signals.com/svn/archives2/every_time_you_add_something_you_take_something_away.php.