The typical product team wants to make products "better" and adding features often seems to be the best approach. We hear "somebody might want to do this!" when the important questions are "Will our primary customer want to?" and "Will adding this make the product more difficult for our primary customer?"
This from: "It's a gazillion degrees in my house right now, but I can't figure out the thermostat controls, so the heat's still on and the air conditioning unreachable. My new Denon receiver/tuner sounds amazing--good thing I'm using it mostly with my iPod; I have no clue how to tune in a radio station. When I bring up the newer versions of Microsoft Word, it looks so utterly foreign and overwhelming to me now that I give up and close it. And all I wanted to do was type a simple letter. Most of you here know that Don Norman talked about this forever in the classic The Design of Everyday Things, but why didn't the designers and manufacturers listen?"
My new car has a GPS. Cool! I use it all the time. But it asks "Add or Replace" when you choose a destination. Huh? I grabbed the book and learned that "Add" means to add this destination to your current route (ie., creating a multi-segment trip) while Replace means to replace your current destination with this new one. I can just hear the developers say "Someone might want to do this!" If the product was planned for a delivery service, this would make sense. But in fact, our primary persona will not want to do it and worse, adding it confuses him or her.