Here's one from the "hey-how-did-I-do-that?"department. I'm not sure what version of iOS this feature was introduced, but I accidentally discovered that on standard apps you can swipe left or right on a list item to reveal a "delete" button.
This is a far more satisfying interaction than the old way, which bombarded the page with a phalanx of red "arm-for-deletion" buttons (that still remains on the standard weather app). The new design is a lot more gentle - and show that someone is still thinkin' hard about how to make a good experience better.
The only downside is I now have to revisit a bunch of old HTML5 mobile web apps and update them.