Why did they delete "Flappy Bird"?

Flappy Bird was pulled from the app stores by its creator Dong Nguyen, who told Forbes that he was a simple man and that Flappy Bird was ruining his simple life so much that he had grown to hate it. He removed the app from stores on Feb. 19, 2014.

Flappy Bird the was No. 1 in the Apple App store and the Android Marketplace. The game mechanics were simple, but the game play was very difficult, which led to a lot of negative feedback and criticism of the game. At the height of the app's popularity, Nguyen earned over $50,000 a day from it.