Casinos and game developers understand how the law of probability works. Let us say that you have a chance of landing a combination for a symbol 50 to 1. If this hits, you will likely get paid 45 to 1. This is how the house edge works. The thing is, a slot is a game of chance. And any game of chance is designed to make a casino earn money. This is not to say that the game is rigged. It just means that it was designed to favour the casino. The same principle applies to many games like blackjack, roulette, and others.