In this post “User experience factor 1: state glue” Martijn van Welie descripes the feedback you get from the iPhone when you delete a mail.

I think Martijn van Welie is right on spot when stating that the iPhones feedback “leads to a very satisfying experience”.

it’s particular important with tactile feedback from a device when there is no physical feedback like haptic feedback. On the iPhone it is well done with small “movie clips”.

The user needs to know that something is happening and what it is that is happening when interacting with a device in order to be able to know if the action was the expected one.

The iPhone does it in a way that makes you do it just for fun, show it to your friends or write a interesting post about it. I myself is being found guilty on all counts.