You come back and spend a few minutes getting dressed, or putting clothes away. Your iPhone is three feet away, but it sits there silent, not making so much as a chirp to let you know that you missed a call. You might stroll out to the kitchen to make dinner, or whatever... The hours go by, and you never knew that your friend called to see if you wanted to meet up for happy hour.
The sheer stupidity of this design was inexcusable in version 1 of the iPhone, but here we are years later and it still hasn't been fixed. But what did Apple do instead? Add repeating notifications (albeit limited to 10) for TEXT MESSAGES. WTF?
Dear Apple: When something major happens in my family, my parents aren't going to TEXT me. If someone called me, I want to know about it.
Do we have to spell this out? A phone should offer the option to periodically notify you with an audible and palpable alert that you've missed a call, until you acknowledge it. Not just five times or 10 times; until you acknowledge it.
Pathetic, and still not fixed in iOS 6.1:
Come on, people! Let's get Apple to fix this. You can submit the suggestion here.
Here's some suggested text, to make it as easy as possible (I'd file under "Design/Ease of use"):
Please implement AUDIBLE periodic notifications of missed calls, which continue for a set number of times or UNTIL CANCELLED.
Callers expect that a modern phone will alert the recipient to missed calls. The iPhone doesn't, which results in missed time with friends and family, missed opportunities, and even a harmed professional image whenever a call comes in while the user is in a noisy environment or away from his phone for a few minutes. The suggestion that users run to check their phones or compulsively pull them out every few minutes insults not only the users, but also the Apple brand.