Phone book is not the best place to keep the phone of the person you talk with most often. It should be on your home screen. Just tap and call, instead of scrolling recent calls history or phone book. A perfect surprise for your girlfriend/boyfriend/husband/wife or simply best friend. Customize the app as you wish, add multiple photos of him/her or both of you. Different photo will appear each time you open the app. In addition you can pin the App Icon to the bottom bar and have the app always visible and at hand.
