Just stop is the logical decision but we are creatures of emotion and the games developers prey on that. At first its $20 for saving yourself 20 hours of grinding, that's a pretty good deal right? What $20? Then in a few more days its another $20 and in a month you're down a few hundred.

Now, you and I, we're smart enough to fall into that trap and see it for what it is. But people in general? The numbers don't lie, just having 5% of your audience, 1 in 20 people, fall into this trap is enough to call your game a massive financial success. I'd bet there's at least one person who reads this, and still unconsciously spends more than they would in cold blood plan to.