Steve Jobs is known as a genius when it comes to user interfaces --never mind Telling a Person from Trash: A Macintosh Computer's Psychological Problem. But with the iPhone, he got a couple of things wrong:

1st, there is no search functionality for emails.

2nd, if you go into Settings --> Sound, there is an option called Silent. That says Vibrate. Turns out the switch has nothing to do with vibrating. If you turn that off, it rings. You turn it on, it does not. Maybe relabel it "Ring"?