Coins. Plenty of games have them scattered around to collect, but few explain why they're there in the first place. If they're so valuable, why did somebody just leave them there?
Leo's Fortune gives a reason. The titular mustached puffball earned his gold fair and square, through hard work and ingenuity. So naturally, when somebody steals it all, he sets out on a quest to regain what is rightfully his. Along the way, he learns a lesson about money, greed, and true value.