I’ve always thought of it this way: a good writer reads a lot of books. They see how other writers solve problems. They pay attention to what’s happening now as much as they pay attention to the classics. Good writers are readers first, but eagle-eyed, careful readers.
I think good developers are the same: they look at other apps. They “read” those apps, the problems they have and how they solve them. They notice trends, they notice new solutions, they notice when things work and when they don’t.
Not every developer does that. Some do, but pretty much limit themselves to Apple apps, which means they’re missing some interesting things. And some developers try but haven’t yet developed the close eye it takes. (It just takes practice.)
There may still be some developers who say there’s no place for style and fashion in UI, that usability is usability and that’s that. They’re mistaken, because part of human nature is to get tired of things and want fresh things, and UI is where the computer meets human nature. Human nature is not going to change on this matter. And I’m glad about that.
-Brent Simmons, in an interview with John Gruber, Daring Fireball, June 3, 2011