I played Cafeteria Nipponica until my fingers bled.
It isn't quite as extreme as it sounds. The screen on my phone has been cracked for the best part of the week as a result of some goon walking into me when I was taking a photo of some ducks. It hasn't shattered yet, but the cracks have been slowly spreading further up the screen, and I caught my index finger on the edge. At first, I thought it was just a scratch and played on, until eventually I realised that the thin smear of red on the screen wasn't the result of a disgruntled customer going all D-Fens on my ass.
It says something about Kairosoft's magic formula that I was compelled to continue. In my review of the developer's recent Android hit Dungeon Village I mentioned the little feedback loops and constant positive reinforcement as a powerful, almost narcotic hook, but there must be more to it than that.