Every once in a while I’ll get super into a game on my iPhone for a brief period of time, and spend countless hours trying to defeat enemies and beat worlds against colorful, pixelated backdrops. After a while, one of two things inevitably happens: either I beat the game quickly and lose interest, or I lose too much and lose interest.

Dragonvale, a dragon-hatching and breeding game.

One such game I spent a lot of time on was Dragonvale, building myself a virtual kingdom to hatch and raise dragons. After a while I realized I’d never get the rare dragons without paying money, which I wasn’t prepared to do, and so I stopped playing. The same is true of Crossy Road; I can’t get past about three hundred hops, and so I just gave up.

Every once in a while, though, comes along a game that manages to walk the fine line between too easy and too hard, and has nearly infinite replayability. Angry Birds is one of those; the levels are easy to win, but almost impossible to win well. And I’m starting to think Super Mario Run is falling into that category as well.

Super Mario Run—an addictive game in an 8-bit world.

I’ve spent an inordinate amount of time tapping away on my iPhone screen at Nintendo’s latest release, and I’ve already beaten the game—the easiest way. But it turns out that every level has not only the goal of completing it, but the goal of collecting five colored coins—three different ways. So now, of course, I’m going back through all the levels and trying to win those coins, which will lead to only more countless hours spent exercising my thumbs.

What games are your favorite time wasters? What have you invested far too much of your life into?