None of them are designed for a large win. Roulette players have devised many betting systems over the years to take advantage of both good and bad streaks. Casual bettors may enjoy the game immensely, but they are unlikely to ever have the kind of night they will remember for years to come.
Before wagering, roulette players should decide not just what betting strategy or system they will use, but also whether to just casually pass the time or try for a roulette win.