Hearthstone. I had to delete it. I downloaded, and was like, "it's a crappy version of MTG". Next thing I know it's 4 hours later and I'm still rocking. 5 nights in a row I stayed up till at least 3 am playing it. It's not that I wanted to exactly, it's just that I literally lost all comprehension of time. After I realized I played for two hours at work one day, I deleted it and never went back.