Little, Irresistible iPhone App Design Elements

What are your favorite iOS interactive design features that get you playing more than what is actually necessary to accomplish what they are supposed to do? For example, everyone love's @path's plus / x button with animated radial list of social sharing choices.

Orchestra's speech wave

buzzfeed.com

Tapping on the Siri button has a sound prompt, but I prefer this wave that really makes it feel like your input counts

Path's animated, radial sharing button that toggles + --> x

Path literally bet the farm on this feature and it really works. In tandem with the scrolling clock, the entire UI hinges on this button and the amazing thing is that it requires users to first tap it to even have a chance to do anything at all, otherwise there are no reminders to action anywhere on the screen. Risky move that paid off big.

Flipboard's Flipper

Flipboard is known for being flippant, and this feature is as satisfying on iPhone as it is on iPad.

Paypal's pin to pay slider

This feature makes a check-in to pay feature actually make sense visually. As much of a fan of Square as I am I prefer this design, very satisfying to pull the pin.

IMDb's extra feature toggle (search, home, & watchlist)

This is a really minor one, but what I like about it is that IMDb figure out how to create an alternative option to the back button for power users without wasting any space. The two little slots let you pull down for extra features - don't see it, no problem you probably aren't a frequent enough user to care, but for those who do, really nice to have.

Gabi's time machine

Gabi is an alternative facebook viewer which I admit I don't use that much, but I really dig this feature that breaks up the elements of time into icons and lets you toggle to different timescales easily.

MLB's game changer

MLB made it really easy to get a quick view of other games within fullscreen live video and even switch over to other live streams by tapping on the boxscore.

Starbucks' physics enabled star tank

I've played with these stars while on line at starbucks pretty much every time I go. This is the digital equivalent of the snow globe and naked lady pen.

The Gogobot sharing hemisphere

Like Path, there's a payoff when you tap the plus button on the bottom sharing dock on Gogobot.

Relevance: the timers

The peelback to show timers, a new take on the soon to be gone iOS Google Maps view changer is well done in Relevance, also the most...relevant of this Flipboard competitor as it takes time into account when curating social content.

Dark Sky: The rainy window

Dark focuses on atrocious weather, so much so that if there's none to show it will feature another part of the world just to show you its ability to present doom and gloom. The rainy window is a shiny toggle that lets you not only see the volume of precipitation but it also controls the time and therefore the view of the map!

Foursquare's 'there's only one picture here' peek-a-boo swipe

Flickr: tlimongello

Foursquare 5.0 continues to let you post multiple photos to your checkins but this time around it teases you if you only have one photo - mari is hiding behind the photo with her camera if you swipe left for more as if to say, hey I'm ready if you take more pictures at this place.

Songkick: music library scan

This is the frankenstein feature - not frankenstein because it's out of place, but because it literally looks like it's generating electricity and should be accompanied by a cry of 'Science!'. Good heavens miss Soundkick you're beautiful!

Circle : The wax-on-wax-off circle of friends navigation

Swipe the right for friends you know, the left for those you don't. Circles are showing up everywhere on the web now and it's totally because of this app, it's UX impact is already far beyond the Circle network.

Taskrabbit: the Wheel of Chores!

I like wheels and this one makes chores seem approachable.